A delicious Hasselback Potato Gratin made with layers of thinly sliced potatoes and yams, coated in a creamy mixture of Gruyère and Parmesan cheese, garlic, and fresh thyme, baked until golden brown and crispy on top.
1: Preheat the Oven to 400° F.
2: In a mixing bowl, mix together the grated Gruyère cheese, Parmesan cheese, heavy cream, garlic, and thyme.
3: Season with salt and pepper, then add in the potato slices, tossing to coat them with the mixture.
4: Grease a 3.5-Quart Casserole Dish with butter.
5: Organize the potato slices into stacks and place them in the casserole dish with their edges aligned vertically.
6: Place yam slices in between the potato stacks as desired.
7: If needed, slice an additional potato, coat lightly with the cream mixture, and add to the casserole.
8: Sprinkle extra Parmesan cheese on top if desired.
9: Cover the dish tightly with aluminum foil and bake for 30 minutes.
10: Remove the foil and continue baking for another 45 minutes or until golden brown and crisp on top.
11: Carefully remove from the oven and let rest for a few minutes before serving.
