Step 1

Heat the oven to 375°F and prepare the baking dish. Arrange a rack in the middle of the oven and heat the oven to 375°F. Coat an 8x8-inch or other 2-quart baking dish with butter or cooking spray; set aside.

Step 2

Peel and slice the potatoes. Peel the potatoes and remove any blemishes. Thinly slice them crosswise (about 1/4-inch thick). Transfer to a large pot.

Step 3

Warm the cream and potatoes on the stovetop. Add the milk or cream, bay leaf, salt, thyme if using, and pepper. (The milk won't cover the potatoes.) Place over medium heat. Gently lift and stir the potatoes a few times with a rubber spatula to make sure all the potatoes get a turn in the warming cream. Heat just until the cream starts to bubble around the edges, about 10 minutes. Pay close attention as the cream heats; it can bubble up quite quickly once it's warm.

Step 4

Transfer the potatoes to the baking dish. Using a slotted spoon, transfer the potatoes to the prepared baking dish and arrange in an even layer.

Step 5

Pour the cream or milk over the top. Remove the bay leaf from the remaining cream mixture. Pour the cream or milk mixture over the potatoes, stopping just below the top layer. Depending on the size of your dish, you may have a little cream left over (save for drizzling at the end if desired).

Step 6

Bake for 50 to 60 minutes. Bake uncovered for 30 minutes. Rotate the baking dish and continue to bake until the dish no longer jiggles when moved, the potatoes are easily pierced with a knife all the way to the bottom, and the top is browned, 20 to 30 minutes more.

Step 7

Cool briefly. Let cool at least 10 minutes on a wire rack. This gives the scalloped potatoes time to finish setting, which will make it easier to slice and serve.

Step 8

Serve the potatoes. The potatoes can be served immediately or kept in a warm oven for half an hour. Serve with a little of the reserved sauce left in the pan drizzled over the top of each serving, if desired.