2CStock or BrothI used chicken, but veggie or beef will work just fine
Kosher Salt and Pepperto taste
2 ½lbYukon Gold Potatoessliced ¼" rounds
Remove fronds. Vertically quarter fennel bulbs, remove root base and vertically slice. Melt butter in a heavy bottomed sauté pan until bubbling. Add fennel slices and a 5-finger pinch of salt to encourage sweating. Stir occasionally, cooking until fennel is beginning to soften and become translucent, 3-4 minutes.Add garlic and stir. Cook until fragrant, 30-45 seconds.Add stock or broth and bring to a simmer. Cook, stirring occasionally, until broth is evaporated and fennel is golden and fork tender.
In the bottom of gratin, casserole or pie dish, spread out a single layer of potatoes, attempting to cover as much of the pan as possible without overlap. Sprinkle with kosher salt and pepper.Add fennel in single layer, stretching to cover as much surface area as possible.Layer remaining potatoes atop fennel. Season with salt and pepper.Sprinkle with parmesan cheese, covering as much surface area as possible. Slowly drizzle in heavy cream, being careful not to disturb the cheese too much. Try to get the cream to touch as much as possible.
Cover tightly with foil. *If you prefer, you can place the gratin in the fridge overnight to bake off for the following day.Preheat oven to 325F. Bake gratin covered for 30-45 minutes, until potatoes are still too al dente to eat, but you can push a fork through. Remove foil and crank heat to 375F. Return to oven for another 30-45 minutes, until top is golden and bubbly and potatoes are easily pierced by a fork. *If topping is browning too quickly, lightly tent foil over top while baking. Do not seal edges as you want some evaporation to take place.Allow to rest for 5-10 minutes, then serve and enjoy!
Fennel can be caramelized ahead of time. Will keep for up to a week in the fridge or up to a month in the freezer.
Gratin can be assembled the night before baking and covered tightly with foil before refrigerating.
If your fennel comes with fronds, save some for roughly chopping and garnishing on top of finished gratin!