Potato-Fennel Gratin

• 2 small fennel bulbs
• 1 yellow onion, thinly sliced
• 2 tablespoons good olive oil
• 1 tablespoon unsalted butter
• 2 lbs russet potatoes (about 4 large potatoes)
• 1 cups plus 2 tablespoons heavy cream
• 2 1/2 cups grated Gruyere cheese (1/2 lb)
• 1 teaspoon kosher salt
• 1/2 teaspoon freshly ground black pepper

1. Preheat oven to 350
2. butter the inside of a 10 x 15 x 2 inch baking dish
3. Remove 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. Saute the fennel and the onions in the olive oil and butter on medium low heat for 15 minutes, until tender.
4. Peel the potatoes, then thinly slice them by hand or with a mandoline. Mix the sliced potatoes in a large bowl with2 cups of cream, 2 cups of Gruyere, salt, and pepper. Add the sauteed fennel and onion and mix well.
5. Pour the potatoes into the baking dish. Press down to smooth the potatoes Combine the remaining 2 tablespoons of cream and 1/2 cup of the Gruyere 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.

fennel bulbs, yellow onion, olive oil, unsalted butter, potatoes, heavy cream, gruyere cheese, kosher salt, freshly ground black pepper

Taken from www.epicurious.com/recipes/member/views/potato-fennel-gratin-50115349 (may not work)