My easy Croissant Breakfast Casserole recipe is destined to be a huge hit with the whole family. Buttery croissants, custardy eggs, and your choice of savory mix-ins are baked into a strata with the most fabulous flaky layers you can imagine! Perfect for serving a crowd, cleaning out the fridge, and filling tummies in a fuss-free way.
This delightfully cheesy, eggy and carb-y croissant breakfast casserole—essentially a souped-up strata—can be thrown together the night before, making it a great recipe for celebratory, stress-free mornings. Strata is typically made with stale bread, eggs, milk and cheese, with the option for add-ins like vegetables or meats, sort of like a savory bread pudding.
This Italian staple is also one of my all-time favorite flexible meals! In the recipe below, I use bacon, swiss, and scallions as my mix-ins, but don’t feel limited. This is a great spot to use up all the last veggies in the crisper drawer, leftover meats from dinner during the week, and little cheese nubs with no purpose. Read the “Optional Variations” section for tons more flavor ideas!
But, while most strata recipes call for regular ol' bread, I took a page out of my old restaurant Marché's book and decided to make a croissant egg bake instead. The result is the best breakfast casserole around. It’s rich and buttery, light and flaky, and completely customizable. If you’re looking for a Christmas morning brunch dish, this bad boy should be top of your list.
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Why You’ll Love This Make-Ahead Breakfast Casserole
- Great for Groups - Whether you’re hosting for the holidays, your kids are having a sleepover, or it’s your turn to put on Sunday Funday, this croissant strata is a winner. One batch makes enough to feed 12, but it’s just as easy to halve or double the recipe depending on your needs.
- Endlessly Customizable - Y’all know reducing food waste at home is one of the easiest ways to keep your grocery budget in check, right? Well, we used to make this easy breakfast casserole at the restaurant to use up leftover croissants or bread, the last bits of cheese from our charcuterie plates, and whatever else we had on hand that we didn’t have any other use for—and you should do the same!
- Quick & Easy - Seriously, friends. This is the easiest make-ahead breakfast bake of all time. Tear up some leftover croissants, mix up a quick egg and milk mixture, then layer it all in a 9x13 with the cheese, meat and veggies of your choice. Once prepped, just pop it in the fridge—all that’s left to do is bake it off in the morning!
Ingredients & Substitutions
As I mentioned earlier, this croissant breakfast casserole is super flexible. I use ham or bacon and swiss cheese for a croque monsieur vibe, but there are endless ways to customize it. Read on for more ideas!
- Large Croissants - Costco’s are fantastic and super affordable, but you should be able to find them in the bakery section of the grocery store you frequent.
- Swiss Cheese - Make sure to buy your cheese in a block and grate it yourself for the best results.
- Ham or Bacon - Leftover holiday ham, Canadian bacon, or cooked bacon (beef, pork, or turkey) will all do the trick!
- Green Onions - I love the slight allium punchiness and green color scallions add to the mix. Feel free to swap in sweet yellow or red onions, shallots, or even caramelized onion if you prefer.
- Eggs - If you can swing it, organic, pasture-raised and humane certified eggs have a more nutrient-dense profile and are better for the environment.
- Milk - Joe and I usually keep whole milk on hand, but at the restaurant we used half n half (made with half milk and half heavy cream) to make the egg bake extra decadent. Feel free to use any percentage of dairy milk you prefer, keeping in mind the more fat, the more custardy it’ll taste.
- Dijon Mustard - Since I was going for a croque monsieur flavor profile, a little mustard made sense. Feel free to swap in another variety of mustard (e.g. spicy brown or whole grain), or omit it depending on your choice of mix-ins.
- Cayenne - Optional, but nice for a little kick.
- Garlic Powder - For the sweet taste of cooked garlic without the fuss of papery skins.
- Butter - Optional for dotting the top before baking. The croissants are already buttery tasting, but a little extra makes our breakfast casserole really shine.
- Kosher Salt & Black Pepper - Just the basics!
How to Make Croissant Breakfast Casserole
Step 1: Prep. Slice the croissants in half like a hamburger bun, cut them into strips, then into bite-sized cubes. Aim for roughly even pieces so they soak and bake evenly. In a large mixing bowl, whisk the eggs until smooth. Add the milk or half-and-half and whisk again until fully combined.
Step 2: Season Egg Mixture. Whisk in the mustard and spices, then season with kosher salt and pepper.
Step 3: Assemble in Layers. Spread the croissant cubes in an even, single layer in the bottom of your baking dish. Sprinkle the shredded cheese over top, then add the ham or bacon and the green onions. Layering the rest of the ingredients like a strata keeps every bite balanced!
Step 4: Soak. Slowly pour the egg mixture over the entire dish, taking care not to disturb the layers too much. Use a spoon or spatula to gently press down any dry croissant pieces so they can start absorbing the custard. It’s okay if some float back up—they’ll continue soaking during the rest.
Step 5: Refrigerate Overnight. Cover the dish with foil and refrigerate it overnight. This gives the croissants enough time to fully absorb the custard, which keeps the casserole tender and cohesive.
Step 6: Bake. When the oven reaches 350°F, transfer the casserole straight from the fridge to the middle rack, keeping it covered with foil to prevent early browning. Bake for about 30 minutes.
Step 7: Uncover & Bake. Remove the foil and return the dish to the oven for another 30 minutes. The casserole should emerge golden brown and puffed with an irresistible aroma.
Step 8: Rest & Serve. Let the baked croissant breakfast casserole rest for 5-10 minutes so it can set, then slice and serve. If you’re feeling extra, add a fried egg on top or a spoonful of béchamel or Mornay sauce. It’s also great on its own!
Optional Flavor Variations
If bacon and swiss isn't your dream flavor combo, don't worry! This strata is easily customizable. Keep the ratio of bread, cheese, egg and milk the same, then fiddle with the other components to suit your tastes. I like to treat this recipe as a “clean the fridge” situation at the end of the week, mixing and matching my leftovers into something that makes sense.
There are a ton of flavor combos out there that work. Turn to your favorite toasted sandwiches, calzones or pizzas for inspiration. Here's just a few ideas to get you started:
- Hawaiian: Take a page from my Hawaiian roll chicken sliders and sub in Hawaiian rolls, diced chicken, cheddar cheese and drained pineapple.
- Supreme: Sub cooked Italian sausage and pepperoni, mozzarella, drained diced tomatoes, sautéed bell peppers and black olives.
- BBQ Chicken: Use shredded rotisserie chicken, BBQ spice rub instead of dijon/cayenne/garlic powder, and smoked gouda instead of swiss.
- Broccoli Cheese: Use leftover curried chicken divan with extra roasted broccoli and cheddar cheese.
- Go Sweet: If you’re not a savory person, lean more into French toast vibes. Omit the cheese (or use a mild, milky cheese like mozzarella), use dried fruit, toasted nuts, and/or chocolate chips instead of green onions and bacon, swap out the dijon mustard for brown sugar or maple syrup, and use cinnamon, nutmeg, or pumpkin pie spice instead of garlic powder and cayenne.
But don’t stop there! Seriously, the sky is the limit once you have the base down. Feel free to make your own delicious combinations using any of the following ingredients (or anything else you can think of that isn’t on here):
- Cheese: Cheddar Cheese, Jack, Pepper Jack, Gouda, Smoked Gouda, Goat Cheese, Quesadilla, Mozzarella, Taleggio, Havarti, Blue Cheese, Edam, Muenster, Asiago, Port Salut OR ANY OTHER MELTY CHEESE YOU LIKE! You can also use vegan cheese if needed.
- Cooked Meat (feel free to omit for vegetarian): Bacon Bits, Dutch Oven Turkey Breast, Breakfast Sausage, Chorizo, Chopped Deli Meat, Shredded Chicken, Pepperoni, or Vegan Meat Crumbles.
- Cooked Vegetables: Roasted Broccoli or Cauliflower, Sautéed Greens (Spinach, Kale, Chard), Caramelized Onion, Shallots, Leeks or Fennel, and/or Sautéed Bell Pepper or Poblano Pepper.
- Seasonings: Fresh Herbs, Dried Herbs and Spices, Pesto, Fresh Green Onions or Chives, or Fresh Minced Shallots.
- Other Ideas: Drained Canned Tomatoes, Roasted Chili Peppers, Sliced Black Olives, Pickled Peppers, or Dried Fruit, Chocolate Chips, Toasted Nuts.
Expert Tips
- Use day-old, high-quality croissants for the best texture. Slightly stale croissants absorb the custard more evenly and hold their structure better. Fresh croissants will still work, especially if you lightly bake them first (like stuffing bread).
- Cut the croissants into similar-sized cubes. Even pieces mean even soaking and even baking.
- Season the custard generously. Mustard, spices, salt, and pepper season the entire casserole. Taste a small spoonful of the custard before pouring it in; a little fingerful should tell you all you need to know.
- Layer with intention. Keep the croissants on the bottom, then the cheese, then the meats and veggies. This strata-style build ensures every bite has a little bit of everything and prevents the heavier fillings from sinking. If you want an extra crispy top, save half of the cheese for sprinkling on last.
- Pour slowly and press gently. A slow pour keeps your layers tidy, and a light press helps the croissants start absorbing the custard without turning mushy. Don’t over-press—you’re just aiming to get the croissants level with the egg mixture while leaving them fluffy.
- Resting overnight is non-negotiable for ultimate flavor. An overnight soak gives the croissants time to fully hydrate, turning the casserole into a cohesive, custardy bake.
- Bake covered first, uncovered second. Keeping the foil on during the first half traps steam and ensures even cooking. Removing it at the end gives you a gorgeous, golden-brown, puffed top.
- If the center jiggles, keep baking. Strata-style breakfast casseroles sometimes need extra cooking time, especially if your fridge is very cold or your baking dish is small (making the casserole extra thick). Look for a mostly set center before pulling it out.
- Let it rest before slicing. A 5-10 minute rest helps everything settle and makes for cleaner slices.
Serving Suggestions
You’ll never hear me complain if you serve this croissant breakfast strata exactly as it is—warm, custardy, and straight from the pan. But if you want to dress it up a bit, a simple side salad is a great place to start. The crisp greens and a splash of acidity balance out all the buttery richness and make the plate look pretty as a picture.
If you’re aiming for extra protein (or just love a good runny yolk), try topping each slice with a fried or scrambled egg. A medium egg with a jammy center is my personal favorite—the yolk becomes a built-in sauce—but you do you.
At the restaurant, we loved adding sauces to play up different flavor profiles. Going for a pizza-inspired version? Serve your slice in a small pool of marinara. Making a classic BEC? A spoonful of béchamel or Mornay sauce instantly gives fancy French vibes. Leaning into Southwestern or Mexican flavors? Try enchilada sauce, salsa ranchera, or a dollop of crema.
For drinks, you can keep things cozy with homemade fancy coffee drinks like a spicy Mexican mocha or pumpkin spice latte. For a special Sunday breakfast, Easter brunch, or another celebration, break out the brunch cocktails! My boozy Christmas coffee is a no-brainer on Christmas morning, but Bloody Marys, Mimosas, and Screwdrivers are always winners.
If you’re feeding a crowd, round out the table with a few easy sides: fresh fruit or berries, yogurt, bacon or sausage links, sliced tomatoes, beans, crispy hash browns, or home fries. Make it a little brunch buffet and let everyone build their ideal plate. Enjoy every stress-free bite!
Storage Instructions
Aside from its versatility, another great thing about this croissant breakfast casserole is how durable it is. Make one over the weekend and simply heat and eat all week long!
- Refrigerator: Once the casserole has cooled to room temperature, cover the dish tightly with foil or transfer to an airtight container. Refrigerate for up to 4 days.
- Freezer: If you want to freeze it, you can, but know the texture of the croissants will soften more once thawed. To do it, wrap cooled portions tightly in plastic wrap and foil, then freeze for up to 2 months. Thaw overnight in the fridge before reheating.
- Reheating Large Portions: To reheat a full pan, cover it with foil and warm it in a 350°F oven for 20-25 minutes, or until heated through. Keeping it covered prevents the top from over-browning while the center warms.
- Small Portions: Use the air fryer to reheat individual slices. Place a piece in a parchment-lined basket (or directly in the basket if it’s sturdy). Air fry at 325°F for 5-8 minutes, checking around the 5-minute mark. If the casserole looks like it’s browning too quickly, tent the slice loosely with a small piece of foil and continue heating until warmed through. The microwave also works perfectly when you’re in a rush. Just heat on medium power in 45-60 second bursts until hot!
FAQs
It can be either! The recipe below is for a savory bacon and swiss version, but you can easily make it sweet by choosing sweet mix-ins (e.g. dried fruit, chocolate chips, nuts), adding a bit of sugar or maple syrup to the custard mix, and swapping in warming spices like cinnamon and vanilla for the mustard, cayenne, and garlic. Hop up to the "optional variations" section for more ideas on how to customize your breakfast casserole.
I don’t know about you, but easy make-ahead dishes like this croissant breakfast casserole are always appealing to me. That way I can wake up in the morning without any chores to do—just pop the baking dish in the oven and enjoy!
More Easy Holiday Breakfast Recipes
Make-Ahead Croissant Breakfast Casserole
Ingredients
- 6 Croissants cubed
- 2 C Swiss Cheese grated
- 2 C Cooked Ham or Bacon cubed
- 2-3 Green Onions sliced, green and white parts both
- 8 Eggs preferably organic and humane certified
- 2 C Milk or half n half
- 1 tablespoon Dijon Mustard
- 1 teaspoon Cayenne
- 1 teaspoon Garlic Powder
- Kosher Salt and Pepper to taste
- 2 tablespoon Butter to dot before baking, optional
Instructions
- Cube croissants, slice green onions and set up mise en place.
- Beat together 8 eggs in a large mixing bowl. Add in your milk or half n' half and beat well. Add in your additional flavorings - in this case, mustard, spices, kosher salt and pepper.8 Eggs, 2 C Milk, 1 tablespoon Dijon Mustard, 1 teaspoon Cayenne, 1 teaspoon Garlic Powder, Kosher Salt and Pepper
- First, place your base layer of croissant (or bread) cubes in the bottom of the casserole dish. Top with shredded cheese, then ham and green onions.Finally, pour the custard mix over top of everything. Pour slowly and carefully to ensure that the layers remain even.Use a spoon or spatula to gently press down any pieces that appear dry. It's fine if they poke back up - once they have a little liquid in there, the process should continue during the resting phase. Dot with butter (if using), then cover the assembled strata with a piece of tinfoil and pop it in the refrigerator to rest overnight.6 Croissants, 2 C Swiss Cheese, 2 C Cooked Ham or Bacon, 2-3 Green Onions, 2 tablespoon Butter
- Preheat oven to 350F. Once the oven hits 350F, pull your assembled casserole from the fridge, and pop it straight in the oven (keeping the foil top) on the middle rack.Bake for about 30 minutes, then pull off the foil and return it to the oven. Bake for another 30 minutes uncovered, until the internal temperature hits 165F.Allow the strata to rest for 5-10 minutes, then slice and serve. Enjoy!
Notes
- No croissants? No problem! Opt for enriched breads like brioche, challah or burger buns instead.
- Rest at least 4 hours prior to baking, and up to overnight.
- For serving, feel free to add a fried egg over the top or a sauce on the bottom (e.g. bechamel) to make things a little fancier. A side salad offers a bit of acidity to cut through the richness, but is not required.
- As long as the bread/croissant, milk, egg and cheese ratio remain the same, you can make this strata in any flavor profile you want. Read the blog post for easy customization ideas!
- Refrigerator: Once the casserole has cooled to room temperature, cover the dish tightly with foil or transfer to an airtight container. Refrigerate for up to 4 days.
- Freezer: If you want to freeze it, you can, but know the texture of the croissants will soften more once thawed. To do it, wrap cooled portions tightly in plastic wrap and foil, then freeze for up to 2 months. Thaw overnight in the fridge before reheating.
- Reheating Large Portions: To reheat a full pan, cover it with foil and warm it in a 350°F oven for 20-25 minutes, or until heated through. Keeping it covered prevents the top from over-browning while the center warms.
- Small Portions: Use the air fryer to reheat individual slices. Place a piece in a parchment-lined basket (or directly in the basket if it’s sturdy). Air fry at 325°F for 5-8 minutes, checking around the 5-minute mark. If the casserole looks like it’s browning too quickly, tent the slice loosely with a small piece of foil and continue heating until warmed through. The microwave also works perfectly when you’re in a rush. Just heat on medium power in 45-60 second bursts until hot!
- Cheese: Cheddar Cheese, Jack, Pepper Jack, Gouda, Smoked Gouda, Goat Cheese, Quesadilla, Mozzarella, Taleggio, Havarti, Blue Cheese, Edam, Muenster, Asiago, Port Salut OR ANY OTHER MELTY CHEESE YOU LIKE! You can also use vegan cheese if needed.
- Cooked Meat (feel free to omit for vegetarian): Bacon Bits, Dutch Oven Turkey Breast, Breakfast Sausage, Chorizo, Chopped Deli Meat, Shredded Chicken, Pepperoni, or Vegan Meat Crumbles.
- Cooked Vegetables: Roasted Broccoli or Cauliflower, Sautéed Greens (Spinach, Kale, Chard), Caramelized Onion, Shallots, Leeks or Fennel, and/or Sautéed Bell Pepper or Poblano Pepper.
- Seasonings: Fresh Herbs, Dried Herbs and Spices, Pesto, Fresh Green Onions or Chives, or Fresh Minced Shallots.
- Other Ideas: Drained Canned Tomatoes, Roasted Chili Peppers, Sliced Black Olives, Pickled Peppers, or Toasted Nuts.
Nutrition
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