Food & Cooking Recipes Main Dish Recipes Casserole Recipes Reblochon-Potato Gratin Be the first to rate & review! By Martha Stewart Test Kitchen Martha Stewart Test Kitchen The recipes developed by our test kitchen team have undergone a rigorous process of development and testing, ensuring that every element is optimal, from ingredient amounts to method and cooking time. This process includes triple-testing recipes to ensure they meet our high standards. The many stellar cooks and food editors who have been part of our team include Sarah Carey, Lucinda Scala Quinn, Jennifer Aaronson, Shira Bocar, Anna Kovel, Greg Lofts, Riley Wofford, Lauren Tyrell, and Lindsay Leopold. Editorial Guidelines Updated on January 20, 2021 Print Rate It Share Share Tweet Pin Email Servings: 6 Reblochon is a French cow's-milk cheese. It has a smooth yellow-to-pink rind and a rich, creamy interior. Ripe Camembert cheese can be used in its place in this delicious potato gratin. Ingredients 3 tablespoons unsalted butter, plus more for the dish 1 tablespoon olive oil 2 yellow onions, sliced into ¼-inch-thick half circles 1 teaspoon sugar 2 ½ pounds all-purpose Maine potatoes, peeled Coarse salt and freshly ground pepper 9 ounces Reblochon cheese, roughly chopped 1 tablespoon fresh thyme leaves Directions Generously butter a 5-cup gratin dish. Melt 1 tablespoon butter and olive oil in a large skillet over low heat. Add onions, sprinkle with sugar, and cook, stirring occasionally, until onions are very soft and golden, 15 to 20 minutes, and set aside. Preheat oven to 400 degrees. Using a mandoline or a knife, slice potatoes 1/8 inch thick. Arrange one-third of the potatoes so they overlap in the gratin dish; sprinkle with salt and pepper. Cover potatoes with half of the reserved onions, half the cheese, and one-third of the thyme leaves. Arrange another one-third of the potatoes so that they overlap; sprinkle with salt and pepper. Repeat layering with remaining onions, cheese, and one third of the thyme. Arrange remaining potatoes on top so they overlap. Melt remaining 2 tablespoons butter; brush it over the final layer of potatoes. Sprinkle the remaining thyme, and season with salt and pepper. Cover tightly with aluminum foil, and place in the oven. Bake for 40 minutes; remove foil, and bake until golden brown, 20 to 30 minutes more. Remove from oven, let stand 5 minutes, and serve. Rate it Print