Cheesy Cauliflower Potato Gratin (Print version)

Tender potatoes and cauliflower baked in a creamy, cheesy sauce for a warm, satisfying side.

# Ingredient List:

→ Vegetables

01 - 1 lb Yukon Gold potatoes, peeled and thinly sliced
02 - 1 lb cauliflower florets
03 - 1 small onion, finely chopped
04 - 2 cloves garlic, minced

→ Dairy

05 - 1 cup whole milk
06 - 1 cup heavy cream
07 - 1 ½ cups grated Gruyère cheese
08 - ¾ cup grated Parmesan cheese
09 - 2 tablespoons unsalted butter

→ Pantry

10 - 2 tablespoons all-purpose flour
11 - ½ teaspoon ground nutmeg
12 - Salt, to taste
13 - Black pepper, to taste

→ Topping

14 - 2 tablespoons breadcrumbs (optional)
15 - 1 tablespoon melted butter (for breadcrumbs, optional)

# How To Make It:

01 - Preheat oven to 375°F. Grease a 9x13 inch baking dish with butter.
02 - Bring large pot of salted water to a boil. Add potato slices and cauliflower florets and cook for 5 minutes until just tender. Drain well and set aside.
03 - Melt 2 tablespoons unsalted butter in a medium saucepan over medium heat. Add onion and garlic, sauté until soft, about 3 minutes.
04 - Stir in 2 tablespoons all-purpose flour and cook for 1 minute, forming a roux.
05 - Gradually whisk in 1 cup whole milk and 1 cup heavy cream. Bring to a gentle simmer, whisking constantly until thickened, about 4 to 5 minutes.
06 - Remove from heat. Stir in 1 ½ cups Gruyère, ⅓ cup Parmesan, ½ teaspoon ground nutmeg, salt, and black pepper until cheese is melted and sauce is smooth.
07 - Layer half of the potatoes and cauliflower in the baking dish. Pour over half of the cheese sauce. Repeat with remaining vegetables and sauce.
08 - Sprinkle remaining ½ cup Parmesan over top. If desired, combine breadcrumbs with 1 tablespoon melted butter and scatter evenly over the surface.
09 - Bake for 40 to 45 minutes until golden and bubbling. Allow to rest for 10 minutes before serving.

# Expert Advice:

01 -
  • It's deceptively simple yet tastes like you spent hours in the kitchen coaxing out deep, nutty flavors.
  • The combination of two cheeses and tender vegetables makes it satisfying enough for a main course, but humble enough to sit alongside roasted chicken or fish.
  • Leftovers are secretly better than the fresh batch, reheating into something even creamier and more forgiving.
02 -
  • The vegetables must be blanched first or the gratin will bake for far too long trying to cook hard potatoes through the sauce, leaving the top burnt and the inside still firm.
  • Keep the cheese sauce warm when you layer it in, because if it's cooled too much it will form a skin and won't meld smoothly with the vegetables.
  • Don't skip the rest time at the end; the gratin will hold together when you scoop it instead of sliding into a puddle of sauce on the plate.
03 -
  • Slice the potatoes on a mandoline if you have one so they're all the same thickness and cook evenly; uneven slices lead to some pieces staying firm while others turn mushy.
  • Keep the cheese sauce slightly thinner than you think it should be because it will thicken more as the vegetables release their moisture during baking.

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