If you are a fan of roasts, you're going to love this simple and delicious recipe for roasted Leg of Lamb with Marmite, Whole Grain Mustard, Garlic and Rosemary. Requiring just a handful of ingredients and a few minutes of prep, this is THE holiday recipe you need to make a special gathering much easier on yourself.

thinly sliced roasted leg of lamb in an oval white serving platter

This simple Leg of Lamb roast recipe requires just 5 ingredients and a few minutes of prep work, and it is supremely delicious. I highly recommend this easy (and fancy!) dish as the star of your holiday celebration!

Growing up, lamb was one of our "special occasion" meals, and this year - 2020, year of the Rona - feels like the year to pull out all the stops for our Christmas dinner. This easy lamb roast is one of the recipes I intend to fix for our celebration this year because Joe, my in-laws and I all love lamb, and this is one of the best recipes I've made so far.

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What is Marmite?
How to Prepare Leg of Lamb for Roasting
Frequently Asked Questions
Need more holiday inspiration? Check out these other yummy recipes:
Marmite & Mustard Leg of Lamb with Garlic and Rosemary
💬 Reviews

table set with white plates, grey napkins, a wine glass being filled with red wine, silver and gold flatware, and a Christmas spread of lamb, carrots, potatoes au gratin and broccolini

While I love making a delicious rack of lamb persillade, my hubby has a difficult time with meat on the bone. Leg of lamb is a great compromise! As a bonus, I don't have to spend time frenching a rack, which makes my life much easier.

Mustard, garlic, and rosemary are well known friends of lamb, but you might not yet be familiar with the wonder that is Marmite. I'm here to espouse all of the virtues of this oft-reviled British spread, especially as concerns roasted meat.

What is Marmite?

If you haven't yet tried this thick, pungent, dark brown salty spread yet, you're really missing out. While the company itself labels Marmite as something you either love or hate, I can almost guarantee that when used in an appropriate fashion, everyone will end up loving Marmite.

Similar to (though sweeter than) Vegemite from Australia, this intensely divisive British spread is made from the byproduct of brewing beer. Made from yeast extract, this savory spread gives an umami punch to anything it touches. When added as an ingredient to meat (like this leg of lamb) it also imparts a beautiful golden brown hue to whatever it touches.

Marmite is also extremely high in vitamins (like vitamin B-12) and nutrients (like folic acid), so much so that it was fed to British troops during World War I. It is also a perfectly acceptable (and vegan!) substitute for bouillon.

While some people like to eat this controversial spread on toast, that's a bit much for me. That said, it's awesome in pasta, soups, stews, and grilled cheese sandwiches. And while I haven't tried it yet, it's apparently a good foil for chocolate too!

How to Prepare Leg of Lamb for Roasting

Preheat oven to 300F. Trim excess fat from roast (leave a thin layer on top), then pat dry with a paper towel.

leg of lamb roast that has been trimmed and had pieces of garlic pushed into small cuts all over

Puncture several dozen times with paring knife, going about ¼ inch deep. Slide slices of garlic into holes.

raw leg of lamb roast that has been sprinkled with salt and pepper

Sprinkle all over (top and bottom) with salt and pepper. Insert a few sprigs of rosemary under the roast before wrapping it back into roast shape.

leg of lamb that has been coated with marmite mustard glaze

Mix together Marmite and mustard in a bowl. Spread all over the top of the roast. Pour wine around base of roasting pan and sprinkle in last few rosemary sprigs.

leg of lamb roast with marmite mustard glaze, small pool of white wine and fresh sprigs of rosemary in a 9 x 13

Roast in 300F oven for an hour, then check the temperature with a meat thermometer. It should register at least 145F before removing it from the oven. Each time you check, baste the roast with the wine and juices. Our roast took about 2 hours.

Rest roast by tenting with foil on a cutting board for at least 15 minutes. In the meantime, reduce wine and drippings by simmering over medium-low heat.

hero shot of roasted leg of lamb that has a marmite mustard seed glaze and is thinly sliced

Thinly slice roast on the bias and serve with reduced jus. Enjoy!

Frequently Asked Questions

What temperature should I aim for with my roast?

While you have to hit at least 145F for food safety, think of lamb the way you would steak. Some people prefer their roasts more on the rare side, while others prefer medium or even well-done. Depending on your preference for pink, you can go anywhere from 145-165F.

If your family is split, not to worry! Simply cut the lamb roast in half and cook in separate dishes. Remove the first half once it hits 145F, and let the other cook longer.

What should I serve with roasted leg of lamb?

All kinds of sides would go deliciously well with this roast. I personally am going to serve this roast with carrots, potatoes and broccolini, but you could choose easily choose asparagus, bitter veggies, peas, radishes, or salads. Also, anything that has anchovies makes a fine pair, as the salty umami-ness (like Marmite!) is a great foil for the gaminess of the meat.

Do you have any good ideas for what to do with the leftovers?

Depending on the size of your roast, you may end up with some leftovers. Don't feel limited to just sandwiches. Sliced leg of lamb can step in for gyros or chicken meat in a pita. Or chop it up and use it in stews or curries. Maybe get bold and make yourself a yummy biryani! Regardless of how you use up your leftovers, they're sure to be delicious.

Need more holiday inspiration? Check out these other yummy recipes:

If you tried this Marmite & Mustard Leg of Lamb roast, let me know how it turned out for you! I love hearing about your kitchen adventures, so please comment below.

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