Centurion gratin-dauphinois

Ingredients

• - 1 teaspoon salt
• - 1/4 teaspoon ground black pepper
• - Pinch freshly grated nutmeg
• - 2 tablespoons unsalted butter, softened
• - 2/3 cup coarsely grated Emmental cheese
• - 2 pounds baking potatoes, peeled and cut crosswise into 1/4-inch slices
• - 5 cups whole milk
• - 2 cloves garlic, very lightly crushed
• - 1 1/2 cups heavy cream
• - 1 1/2 cups crème fraiche (or sour cream)