Potato, Fennel, and Leek Gratin

Ingredients

• 4 large potatoes, peeled and thinly sliced
• 2 leeks, white and light green parts only, thinly sliced
• 1 fennel bulb, thinly sliced
• 2 cloves garlic, minced
• 2 tablespoons olive oil
• 1/2 teaspoon salt
• 1/4 teaspoon freshly ground black pepper
• 1 cup heavy cream or half and half
• 1/2 cup grated Parmesan cheese

Directions

1. Set an oven rack in the middle position, then preheat to 400°F. Use 1 Tbs. of the butter to coat the base and sides of a 10×15-inch (4 quart) baking dish. Add the potatoes, cream, garlic, 1-1/2 tsp. salt, and 1/2 tsp. pepper to an 8-quart pot. Set it over medium heat, bring everything to a gentle simmer, and cook for about 8 minutes, stirring now and then, until a fork meets just a little resistance in the potatoes.
2. While that cooks, melt the remaining 2 Tbs. butter in a sturdy 12-inch skillet set over medium heat. Stir in the fennel seeds and cook only until their scent blooms, about 30 seconds. Add the leeks and fennel, sprinkle them lightly with salt and pepper, and cook for 8 to 10 minutes, stirring from time to time, until they have just softened.
3. Fold the leek-fennel mixture into the potatoes with a gentle hand. Scrape everything into the prepared dish and spread the vegetables into an even layer. Sprinkle the cheese over the top, then bake for 35 to 40 minutes, until the top is richly browned, the cream looks reduced and thick, and a knife slips into the potatoes easily. If the surface is darkening before the vegetables are fully cooked, tent the dish loosely with foil. Cool for 10 to 20 minutes before you serve it.