This gratin combines sweet potatoes and gold potatoes to make a simple and rich side dish or a vegetarian main course. For a dairy-free version, substitute stock for the cream and omit the parmesan cheese. It can be baked in advance and kept warm or reheated before serving.
Preheat the oven to 400°F. Lightly oil an 8-inch cast iron skillet with the olive oil. Combine the thyme, salt and pepper in a small bowl.
Place the sweet potato slices and the gold potato slices in separate bowls. Toss each with half of the seasoning mixture.
Pour the half and half over the potatoes. Cover with foil and put the skillet on a baking sheet to catch any drips. Bake for 40 minutes, then remove the foil and top with the cheese.
Continue baking until the liquid is completely absorbed and the cheese is nicely browned, 15-20 minutes more. Remove the gratin from the oven and allow to set for 20 minutes before serving in wedges.
Copyright 2021 Lynne Curry