• Sam Burgess

Gruyère & Butternut Squash Gratin

Updated: Jan 29

We at the Test Kitchen wanted to start sharing more out of the box Thanksgiving dishes, starting with this cheesy, aromatic, and savory baked side dish: Gruyère & Butternut Squash Gratin.

Gratins are great because you can take as much or as little as you like, and they truly taste better a day or two after baking them, making them prime for reheating. Completely vegetarian and teeming with rosemary and garlic, this might become a mainstay for your big feast!

potato, leeks, gruyere cheese, garlic, rosemary, butternut squash and classic cleaver

Gratin originates from French cuisine and are usually prepared in a shallow dish of some kind, either a casserole or cast iron dish. A gratin is baked or cooked under an overhead grill or broiler to form a golden crust on top and is often served in its baking dish. Most popular is a potato gratin or ‘Gratin de Pommes de Terre’.

We decided to take it to another level of flavor and texture by substituting some of the potatoes for a rich and tender butternut squash. This substitution gives a much stronger base of flavor, as the butternut will combine with the other flavors and slightly sweeten as it cooks. Not to mention the squash provides a nutritional boost of fiber and vitamins compared to straight potato. The vegetables may leave behind excess liquid when sliced, so be sure to wipe the vegetables with a clean towel.

Classic cleaver split a whole butternut squash with ease

Our Classic Cleaver knife makes quick work of the thinly sliced potato and butternut squash. This sharp and balanced blade basically did all the work for us! A normal knife like our Nakiri Vegetable knife or Bunka knife do wonders as well on these tougher fall vegetables. (It’s never too early for a Christmas gift!)

The cheese we used was a nutty Gruyère, a cousin of Swiss cheese. Gruyère is classified as a Swiss-type or Alpine cheese, and is sweet but slightly salty, with a flavor that varies widely with age. It is often described as creamy and nutty when young, becoming more assertive, earthy, and complex as it matures. This is a very important ingredient, as it contrasts the sweetness of the butternut and plays well with the leeks and rosemary.

butternut squash slices next to a Forge To Table Classic Cleaver

The Gruyère cheese is layered between the gratin, but also as a crunchy and salty crust on top of the dish. It can be substituted with other assertive cheeses, such as aged Swiss, sharp cheddar, or white cheddar cheese--but we recommend sticking to the good stuff! Always grate cheeses like these fresh.

The aromatic ingredients start with a base of leeks, which bring a sweet and savory flavor when sauteed in extra virgin olive oil. Garlic brings pungency and a huge savory kick to the party as well. Once these two are cooked until translucent, rosemary and nutmeg are added for a sharp and bright herb flavor, and a slightly sweet note from the nutmeg. Seasonings like salt and pepper follow, as well as half & half for a creamy base to bring it all together.

Sauteed leeks and garlic with rosemary, nutmeg and half-and-half

Once it cools slightly, pour the seasoned cream mixture over the sliced potato and butternut squash, and be sure to toss well so that the seasoning gets between every layer of the gratin. Lightly spray a baking dish and start layering the potato and squash together. Once a third is in the pan, sprinkle with some of the freshly grated Gruyère cheese, and get back to stacking! Once the second layer is done, sprinkle with more cheese, and top with remaining vegetables and any cream mixture.

Layers of butternut squash, potato, and gruyere cheese in a dish

Bake in a preheated oven for about 20 minutes, before topping with remaining cheese and back into the oven until the vegetables are easily pierced with a knife and the cheese is bubbly & browned. Hopefully, you can wait a few minutes before diving in!

We hope you find inspiration in this dish! Substitutions in the ingredients and herbs are encouraged, just don’t stray too much from the proportions. Happy cooking, friends!

Gruyère & Butternut Squash Gratin

Amazing Fall flavors come together in this dish, between the sweet butternut squash, salty cheese, and aromatic rosemary & nutmeg. The Gruyère cheese toasts on top of the gratin for a nutty flavor that makes the dish pop into an irresistible and comforting holiday side!

Recipe by Sam Burgess

Forge To Table

Prep Time: 30 minutes

Cook Time: 1 hour

Makes: 6 servings


  • 2 teaspoon extra virgin olive oil

  • 1 cup leeks, whites only, sliced

  • 1 tablespoon garlic, minced (~2 cloves)

  • 1 cup Half & Half cream

  • 1 teaspoon fresh rosemary, chopped

  • 1-½ teaspoon kosher salt

  • ¼ teaspoon black pepper, freshly ground

  • ½ teaspoon nutmeg

  • A dash of cayenne pepper (optional)

  • 1 pound butternut squash, peeled, halved, seeded (about half a large squash)

  • 1 pound Yukon Gold potatoes

  • 4 ounces Gruyère cheese, freshly shredded (~1-½ cups)

  • Cooking Spray, as needed

  • Picked rosemary leaves, for garnish


  1. (PREP AROMATIC MIXTURE) Preheat the oven to 350F degrees. In a non-stick skillet or saute pan, heat extra virgin olive oil over medium heat. Add leeks and garlic, and cook, stirring often, until translucent, about 3 minutes. Remove from heat and stir in half-and-half, rosemary, salt, pepper, nutmeg, and cayenne pepper.

  2. (PREP BUTTERNUT) Using a Forge To Table Cleaver or Nakiri Vegetable Knife, thinly slice peeled butternut squash close to ⅛ inch. Slice skin-on Yukon Gold potatoes slightly thinner than the squash. Use a clean kitchen towel to wipe away any excess moisture from the vegetable slices. Use your hands to toss the squash and potatoes with the warm cream mixture, making sure that the seasonings get between each layer.

  3. (ASSEMBLING THE GRATIN) Use a box grater to shred gruyere cheese. Spray a 10” pie dish or 1-½ quart baking dish with cooking spray. Arrange ⅓ of the vegetable slices in an even layer and top with 1 ounce (or ¼) of the shredded cheese. Top with another ⅓ of the vegetable slices and another 1 ounce of cheese. Finally, top with the remaining squash and potato, pouring any remaining cream mixture over the top. Reserve remaining cheese.

  4. (BAKE THE GRATIN) Place the gratin dish on a sheet tray and bake in the preheated oven for 20 minutes. Remove from oven and sprinkle remaining cheese on top before continuing to bake until a knife easily pierces thru the gratin and the cheese browned, about 35-45 minutes more. Let cool slightly, divide into 6 or 8 portions, and garnish with rosemary before digging in!

Chef’s Notes:

  • Honeynut squash or acorn squash can be used in place of butternut squash.

  • Aged swiss, sharp cheddar, or white cheddar can be substituted for the gruyere cheese if desired.

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