- 3 eggs
- 3 cups buttermilk
- 1 tablespoon fresh thyme leaves
- 2 teaspoons kosher salt
- 1/8 teaspoon freshly ground pepper
- 2 pounds baking potatoes, peeled and cut into 1/8-inch slices
- 2 pounds Granny Smith apples (unpeeled), cut into 1/8-inch slices
- 1 pound Swiss cheese, shredded
- 1/4 pound Parmesan, grated
- Heat oven to 400° F.
- Coat a 3 1/2-quart casserole with cooking spray. In a medium bowl, whisk together the eggs, buttermilk, thyme, salt, and pepper; set aside.
- Arrange a layer of slightly overlapping potatoes in the casserole. Cover with a layer of apples and sprinkle with a third of each cheese. Pour a third of the egg mixture on top. Make 2 more layers.
- Bake, covered, 1 hour, 15 minutes. Remove cover and bake another 15 minutes or until the potatoes are tender. Remove from oven. Serve warm or at room temperature.