Potato Gratin

Place oven rack at the lowest possible position and preheat oven to 350 degrees F. Generously butter a baking dish of appropriate size that the gratin will have a thickness of 1 to 1 1/2 inches (3-quart casserole or rectangular baking dish). In a saucepan, heat up cream with nutmeg and garlic, if using. Clean leeks and roughly chop. Peel potatoes, if desired (I leave the peel on), and cut into thin 1/8-inch thick slices, no thicker. Make sure that the potato slices are all of the same thickness. In the prepared gratin dish, layer potato slices in an overlapping pattern, sprinkle evenly with leeks, seasoning with salt and pepper, as you go. Remove cream from heat and pour a little over potatoes and leeks. Repeat, making more layers. Place gratin on a foil-lined baking sheet located on the lowest oven rack and bake, uncovered for about 40 to 45 minutes* or until the top is golden brown, cream has thickened** and potatoes are tender when a knife is inserted. Let rest at least 15 minutes before slicing and serving. *Note: Remove from the oven the moment you see any butterfat appearing around the edges of the dish. **Note: Cream will set up more as it cools. Make Ahead Note: The gratin can be made early in the day; reheat in a 325 degree oven. Makes 6 to 8 side-dish servings.