Ingredients
- 2 tbsp butter, softened
- 6 to 7 large Yukon gold or yellow-flesh potatoes (try to have the same size)
- 2 tbsp butter, melted
- 1 tsp salt
- 1/2 tsp pepper
- 1 tsp garlic powder
- 1/2 cup heavy cream or half-and-half
- 1/2 cup milk (whole or low-fat)
- 1/2 cup shredded white cheddar
- 1/2 cup Parmesan, divided
- 1/2 tsp ground nutmeg
- 1 tbsp chopped thyme
- 1/2 tsp harissa powder
- flaky finishing salt
Directions
- Preheat the oven to 400 F. Coat a 9or 10-inch cast-iron skillet or round baking dish with the softened butter.
- Using a mandolin or very sharp knife, cut 6 of the potatoes crosswise into 1/8-inch rounds. Gently pat them dry with a paper towel.
- Place the potato rounds in a large bowl. Add the melted butter, salt, pepper, and garlic powder. Toss to coat.
- In another large bowl, mix together the cream, milk, Cheddar, 2 tablespoons of the Parmesan, and the nutmeg. Working in batches, place the potato rounds in the milky cheese mixture, tossing to coat each round well.
- Arrange the potato rounds in the prepared skillet in tight concentric circles. If you don't have enough to fill your dish, slice an extra potato and coat it in enough slices to finish. Pour any remaining mixture evenly over the potatoes; it should reach about halfway up the sides, but no more.
- Cover with foil and bake for 45 minutes. Remove the foil and bake for 20 minutes more. Meanwhile, combine the remaining Parmesan with the thyme and harissa. Evenly sprinkle the cheese mixture over the potatoes and bake until bubbling and browned, about 20 minutes. Sprinkle with flaky salt.
Note
- Leftovers reheat well; warm in a 300 F oven for 10 to 15 minutes.