"This is the simplest way I know to make a potato gratin. Simmering the vegetables in the milk precooks them somewhat, shortening time in the oven and flavoring the milk, as well. You can easily vary this gratin by substituting some of the potatoes with other root vegetables, such as celery root, turnips, rutabagas, or parsnips. Yukon golds make a beautiful golden gratin, but I also like russets, and sometimes I mix varieties. There will be some leftover gratin, which is always welcome reheated the next day for a simple lunch served with a tossed salad." –Deborah Madison
4 cups 2% reduced-fat milk
2 cups thinly sliced leek (about 2 large)
1 teaspoon salt
1/4 teaspoon freshly ground black pepper
3 pounds baking potato, peeled and cut into 1/4-inch-thick slices
2 thyme sprigs
1 bay leaf
1 garlic clove, minced
1 cup (4 ounces) shredded Gruyère cheese
How to Make It
Preheat oven to 375°.
Place milk, leek, salt, pepper, potato, thyme, bay leaf, and garlic in a Dutch oven; bring to a boil. Cover, reduce heat, and simmer 10 minutes or until potatoes are tender. Discard thyme and bay leaf.
Spoon half of the potato mixture into a 13 x 9-inch baking dish coated with cooking spray. Sprinkle with 1/2 cup cheese. Top with remaining potato mixture and remaining 1/2 cup cheese. Bake at 375° for 1 hour or until golden brown. Let stand for 10 minutes before serving.