I make one based on a Cook's Illustrated recipe. It is similar to the above. If I use all-purpose potatoes I do not rinse them; I do if using bakers. Note: For the best results for either of these recipes (or any potato gratin), the potatoes need to be sliced evenly and quite thin. Use a mandoline if you have one; if slicing by hand be steady and deliberate.
1 large clove garlic, peeled and crushed
1 Tbls unsalted butter, softened
2 1/4 c half-and-half
1 1/4 tsp table salt
1/8 tsp ground white pepper
1 small bay leaf
1 sprig fresh thyme
pinch fresh ground nutmeg
pinch cayenne pepper (optional)
2 pounds all-purpose potatoes, peeled and sliced 1/8-inch thick or less
2 Tbls grated gruyere or asiago
Adjust oven rack to center position and preheat oven to 350. Rub bottom and sides of 5-6 cup gratin dish or shallow baking dish with garlic. Mince remaining garlic and set aside. Once garlic in dish has dried, about 2 minutes, spread dish with half the butter.
Bring half-and-half, salt, pepper, bay, thyme, nutmeg, cayenne (if desired), potatoes, and reserved garlic to boil in medium saucepan over medium-high heat, stirring occasionally (liquid will just barely cover potatoes). Reduce heat and simmer until liquid thickens, about 2 minutes. Remove the thyme and bay.
Pour potato mixture into prepared dish; shake dish or use fork to distribute potatoes evenly. Gently press down potatoes until submerged in liquid; dot with remaining butter.
Bake until top is golden brown (basting once or twice during first 45 minutes) about 1 hour 15 minutes. Let rest 5 minutes and serve. If using the optional cheese, sprinkle on for the last 15 minutes of baking.