1 garlic clove, peeled and halved
1 tablespoon butter, softened
2 1/2 pounds russet potatoes, peeled and very thinly sliced
3 cups milk or a combination of half-and-half and milk
1 teaspoon salt
1/4 teaspoon freshly ground black pepper
Pinch of freshly grated or ground nutmeg
1 cup grated Gruyere or Fontinella cheese
Preheat oven to 350 F. Rub a shallow, 12-inch, 3-quart baking dish (or gratin dish) with the garlic clove. Let dish dry, then coat with the softened butter.
In a large saucepan combine the potatoes, milk or half-and-half combination, salt, black pepper and nutmeg. Bring mixture to a gentle boil over medium heat, then cook and stir until liquid thickens slightly, about 5 minutes. Pour mixture into prepared dish. Press down on top layer to submerge potatoes.
Sprinkle with the cheese. Bake in preheated oven until top is golden and potatoes are tender, about 45 minutes to 1 hour.
Makes 6 to 8 servings.
— Adapted from "Joy of Cooking," by Irma S. Rombauer, Marion Rombauer Becker and Ethan Becker.