Step 1

Preheat the oven to 350°F and set an oven rack in the middle position. Grease an 8-inch (or 2-quart) baking dish with butter.

Step 2

In a large mixing bowl, toss the potatoes with the salt and pepper until evenly coated.

Step 3

Arrange some of the potato slices, edges overlapping, in a single layer on the bottom of the prepared baking dish. Sprinkle a quarter of the cheese over the potatoes, and then pour a quarter of the cream over the cheese. Repeat with the remaining potatoes, cheese, and cream, forming 4 layers. Pour any leftover cream over top.

Step 4

Place in the oven and bake, uncovered, for about an hour, or until the potatoes are tender when pierced with a knife and golden brown on top. Let the dish settle on the counter for about ten minutes. Sprinkle with fresh thyme, if using, and then serve.

Step 5

Make Ahead: This dish can be assembled a day ahead; cover tightly with plastic wrap (pressing the wrap directly against the potatoes so they don’t discolor), store in the refrigerator, and bake before serving. The potatoes on top will still discolor a bit in the fridge, but it shouldn't be noticeable after baking.