2 small fennel bulbs
1 medium yellow onion, thinly sliced
2 tablespoons olive oil
1 tablespoon unsalted butter
2 pounds russet potatoes (4 large potatoes)
2 cups plus 2 tablespoons heavy cream
10-12 ounces Gruyère D’Alpage, grated
1 teaspoon kosher salt
fresh ground pepper
Preheat the oven to 350 degrees F.
Butter the inside of a 10x15x2 inch (10-cup) baking dish.
Remove the stalks from the fennel and cut the bulbs in half lengthwise. Remove the cores and thinly slice the bulbs crosswise, making approximately 4 cups of sliced fennel. Sauté the fennel and onions in the olive oil and butter on medium-low heat for 15 minutes, until tender.
Peel the potatoes, then thinly slice them by hand or with a mandoline. Mix the sliced potatoes in a large bowl with 2 cups of cream, ¾ of the Gruyère, salt, and pepper. Add the sautéed fennel and onion and mix well.
Pour the potatoes into the baking dish. Press down to smooth the potatoes. Combine the remaining 2 tablespoons of cream and the rest of the Gruyère and sprinkle on the top. Bake for 1 1/2 hours, until the potatoes are very tender and the top is browned and bubbly. Allow to set for 10 minutes and serve.
Adapted from Ina Garten, the Barefoot Contessa.