Ingredients

Makes 12 servings

　　1 tablespoon unsalted butter, at room temperature

　　2 large sweet potatoes, peeled and thinly sliced (use a sharp knife, a mandoline, or a food processor with the slicing disc attached)

　　1/2 large Idaho potato, peeled and thinly sliced

　　1 cup heavy cream

　　1 pinch ground nutmeg

　　1 pinch freshly ground black pepper

　　Kosher salt to taste

　　3 ounces Gruyère, grated (about 1 cup)

　　

Step 1

1. Preheat oven to 400°F. With the butter, grease a 12-capacity muffin pan.

　　

Step 2

2. In a large bowl, toss together the sweet potatoes, Idaho potato, cream, nutmeg, pepper, and salt.

　　

Step 3

3. Layer the potato slices in each muffin cup until 3/4 full, then top off the muffin cups with any remaining cream. Sprinkle each gratin with some of the cheese. Cover the pan loosely with tinfoil and bake for 20 minutes.

　　

Step 4

4. Remove the tinfoil and continue to bake until the potatoes are fork-tender and the cheese is golden brown, 10 to 15 minutes more. Remove and let cool for 5 minutes before serving.