4 large sweet potatoes, peeled and sliced into 1/8 inch rounds
2 cups heavy cream
3 tablespoons butter
3 cloves garlic, minced
1 tablespoon fresh thyme, chopped
1 teaspoon fresh rosemary, finely minced
1 cup grated Parmesan cheese
1 teaspoon salt
1/2 teaspoon black pepper
1/2 teaspoon ground nutmeg
Instructions
Start by preheating your oven to 375 degrees Fahrenheit. Grease a 9 by 13 inch baking dish generously with butter or a light coating of oil to ensure the potatoes do not stick to the edges during the long baking process.
Peel your sweet potatoes and use a sharp knife or a mandoline slicer to create uniform rounds about 1/8 inch thick. Keeping the slices consistent is the secret to ensuring every piece of potato cooks through at the exact same rate.
In a medium saucepan over medium heat, combine the heavy cream, minced garlic, thyme, rosemary, salt, pepper, and nutmeg. Bring the mixture to a very gentle simmer for about 5 minutes, allowing the aromatics to flavor the cream. Remove from heat and stir in the butter until melted.
Arrange about one third of the sweet potato slices in an even layer in the bottom of your prepared baking dish. Pour one third of the cream mixture over the top and sprinkle with a portion of the Parmesan cheese. Repeat this process for two more layers, finishing with a generous topping of cheese.
Cover the dish tightly with aluminum foil and bake for 40 minutes. After 40 minutes, remove the foil and continue baking for another 20 minutes, or until the potatoes are fork tender and the top is beautifully browned and bubbling. Let the dish rest for 10 minutes before serving to allow the sauce to set.
