Serves six to eight.
*Note: The best gruyere cheese is made by Emmi and is called Le Gruyere Reserve (it MUST say Reserve on the cheese wheel). If you buy this from Kroger, it will say "cave aged" on the label. There is another Le Gruyere by Emmi that is sold pre-packaged, but it is very hard and waxy and not nearly as good.
2 lb. Yukon Gold or russet potatoes, peeled
3 cups whipping or heavy cream
1 tsp. coarse salt
1/8 tsp. freshly ground black pepper
Generous pinch of freshly grated nutmeg
2 cloves garlic, peeled and smashed
3/4 cup finely shredded Gruyère, Emmental, or Comté
Heat the oven to 400°F.
Using a very sharp knife or a mandolin, carefully cut the potatoes into 1/8-inch slices (no thicker). Put the potatoes in a large heavy-based saucepan and add the cream, salt, pepper, nutmeg, and garlic. Cook the mixture over medium-high heat until the cream is boiling, stirring occasionally (very gently with a rubber spatula so you don't break up the slices). When the cream boils, pour the mixture into a 2-1/2- or 3-qt. baking dish. If you don't want a tender but garlicky surprise mouthful, remove and discard the garlic cloves. Shake the dish a bit to let the slices settle and then sprinkle the surface with the cheese.Bake in the hot oven until the top is deep golden brown, the cream has thickened, and the potatoes are extremely tender when pierced with a knife, about 40 min. Don't worry if the dish looks too liquidy at this point; it will set up as it cools a bit. Before serving, let the potatoes cool until they're very warm but not hot (at least 15 min.) or serve them at room temperature.
Notes: I didn't have any garlic cloves, so I used about 1/2 tsp of garlic powder instead. And I went with the Gruyere cheese, since it's also what I use in the Spinach Gratin. It turned out great.