Slice the potatoes: Wash and peel (if you prefer) your potatoes. Using a madoline, food processor with slicing blade, or a sharp knife, slice them thin and as evenly as possible. About 1/8 inch thick. This helps them cook evenly and gives you those tender, creamy layers.
Simmer the cream: In a saucepan, warm the heavy cream with garlic, butter, rosemary, bay leaf, salt, pepper, and nutmeg. Let it gently simmer for about 10 minutes so the flavors meld together.
Layer the dish: Preheat oven to 350 °F. Grease a 9x13 inch baking dish with butter. Layer the thin slices of potato with a sprinkle of cheese between each layer. Be sure to save cheese for the top.
Pour the cream: Remove rosemary and bay leaf, then pour the warm cream mixture over the layered potatoes.
Bake: Cover with foil and bake for 1 hour or until potatoes are tender when pierced with a knife.
Top with more cheese: Remove foil, sprinkle remaining cheese over the top, and bake uncovered for another 15-20 minutes, until the top is golden and bubbling.
Rest & serve: Let stand for 10 minutes before serving so the cream thickens and layers hold together.
