Onion Potato Gratin

Onion potato gratin with sliced Yukon Gold potatoes, baked with onions, with heavy cream and Gruyere and Parmesan cheeses.

  • Prep time: 15 minutes
  • Cook time: 50 minutes
  • Yield: Serves 4

Ingredients

  • 1 1/2 pounds Yukon Gold potatoes, peeled, cut into 1/4 inch thick slices
  • 1 large yellow onion, thinly sliced
  • 2 tablespoons unsalted butter
  • Salt
  • 2 teaspoons Herbes de Provence, or dried thyme
  • 1/2 teaspoon white pepper
  • 1/2 teaspoon nutmeg
  • 1 cup (packed) grated Gruyere cheese (about 4 oz)
  • 8 tablespoons (packed) freshly grated Parmesan cheese (about 2 oz)
  • 2/3 cup half-and-half (half cream, half milk)

Method

1 Preheat oven to 400°F.

2 Boil the potatoes: Boil the potatoes for 4 minutes in salted water (1 tablespoon of salt for 2 quarts of water). Drain and set aside.

3 Sauté the onions, sprinkle with salt and herbs: Heat the butter over medium-high heat in a large sauté pan and cook the onions, stirring occasionally, until they are softened, about 5 minutes.

Sprinkle them with salt and the Herbes de Provence. Turn off the heat and set aside.

4 Layer potatoes, cheeses, onions, nutmeg in baking dish, pour over with half and half: Spread half of the sliced potatoes over the bottom of an 11x7-inch baking dish (Pyrex works well). Sprinkle well with salt and white pepper.

Sprinkle with about a third of the Gruyere and Parmesan cheeses. Top with the onions, the nutmeg and another 1/3 of the cheeses.

Layer the remaining sliced potatoes on top of the cheeses.

Pour the half and half over everything. Sprinkle again with salt and pepper.

Sprinkle the remaining one-third of the cheeses over everything. (At this point you can make a day ahead, just cover and refrigerate until time to cook.)

5 Bake: Bake uncovered in 400°F oven until cream thickens and everything is nicely browned, about 25-30 minutes.