Winter Vegetable Gratin Gruyere (Print)

A golden casserole of winter vegetables, creamy sauce, and Gruyere cheese, perfect for hearty meals.

# What You Need:

→ Vegetables

01 - 2 cups butternut squash, peeled and thinly sliced
02 - 2 cups parsnips, peeled and thinly sliced
03 - 2 cups Yukon Gold potatoes, peeled and thinly sliced
04 - 1 cup leeks (white and light green parts), thinly sliced

→ Sauce

05 - 2 tablespoons unsalted butter
06 - 2 tablespoons all-purpose flour (substitute gluten-free flour if needed)
07 - 1 1/2 cups whole milk
08 - 1 cup heavy cream
09 - 1/2 teaspoon ground nutmeg
10 - 1/2 teaspoon salt
11 - 1/4 teaspoon ground black pepper

→ Cheese & Topping

12 - 2 cups Gruyere cheese, grated
13 - 1/3 cup grated Parmesan cheese
14 - 1/2 cup fresh breadcrumbs (use gluten-free if preferred)
15 - 1 tablespoon olive oil
16 - 1 tablespoon fresh thyme leaves (optional)

# How To Make It:

01 - Preheat the oven to 375°F. Butter a 9x13-inch baking dish.
02 - Peel and thinly slice butternut squash, parsnips, potatoes, and leeks.
03 - Melt butter in a saucepan over medium heat. Stir in flour and cook for 1 minute.
04 - Gradually whisk in whole milk and heavy cream, cooking until the sauce thickens and smooths, about 3 to 5 minutes.
05 - Stir in ground nutmeg, salt, and black pepper. Remove the sauce from heat.
06 - Arrange half of the sliced vegetables in the baking dish in a slightly overlapping pattern. Sprinkle with half of the grated Gruyere cheese.
07 - Layer the remaining vegetables over the first and top with the remaining Gruyere cheese.
08 - Evenly pour the warm sauce over the layered vegetables and cheese.
09 - Combine breadcrumbs, Parmesan cheese, olive oil, and thyme in a small bowl. Sprinkle evenly over the top of the casserole.
10 - Cover loosely with aluminum foil and bake for 30 minutes.
11 - Remove the foil and continue baking for 20 minutes or until golden and bubbly.
12 - Allow to rest for 10 minutes before serving to set.

# Expert Advice:

01 -
  • The Gruyere melts into every crevice, creating pockets of nutty, salty richness that make each bite feel indulgent.
  • Winter vegetables get sweet and tender under that creamy sauce, proving that root vegetables deserve more love than they usually get.
  • It looks impressive enough for guests but forgiving enough that you can prep it hours ahead and just slide it in the oven when people arrive.
02 -
  • Slice your vegetables as evenly as possible, or the thick pieces will stay firm while the thin ones turn mushy.
  • Do not skip the resting time after baking, or your beautiful layers will collapse into a puddle on the plate.
  • Warm sauce is key because cold sauce will seize up and refuse to spread smoothly over the vegetables.
03 -
  • Use a mandoline to slice the vegetables paper-thin and save yourself twenty minutes of knife work and frustration.
  • Let the gratin cool for a full 10 minutes before cutting into it, or the layers will slide apart and you will lose that beautiful cross-section.
  • If the top browns too quickly, tent it loosely with foil for the last few minutes so the vegetables finish cooking without burning.

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