2 pounds Yukon gold potatoes
1 1/2 cups coarsely grated Gruyere cheese (about 6 ounces)
1/2 cup milk, heated just to boiling
1/2 cup heavy cream, heated just to boiling
Freshly grated nutmeg (spicy variation 1/4 tsp cayenne pepper)
Salt and pepper, to taste
Note: heavy cream and milk can be replaced by 1 cup half and half
Preheat oven to 400 degrees and butter a 3-quart gratin or shallow baking dish w. 1 tblsp butter. Bring a large saucepan of salted water to a boil. Peel potatoes and cut into thin slices (about 1/8-inch thick). Add potatoes to boiling water and parcook 4 minutes. Drain potatoes well in a colander.
In gratin or baking dish arrange potatoes, overlapping them, in 3 layers, sprinkling first 2 layers each with 1/2 cup Gruyere and salt and peppers to taste.
Heat milk, cream and nutmeg (or) cayenne in a small bowl. Season mixture with salt and pepper and pour evenly over potatoes. Sprinkle potatoes with remaining 1/2 cup cheese and bake 30 minutes, or until top is golden and potatoes are tender.