Simple and delicious recipe for creamy French-style potatoes baked in a skillet! Tasty layers of sliced potatoes in a creamy sauce with leeks and Gruyere cheese. Serve this warm as a side dish or with a green salad for a light supper or brunch dish.
Heat the oven to 350 degrees (180 C) with the rack positioned in the center of the oven.
Melt 1 tablespoon of the butter in an 8-10-inch cast iron skillet or heavy skillet over medium heat. Add the leeks and cook until wilted and golden, stirring frequently. Remove the leeks from the pan and set aside. Wipe out the pan.
Whisk the eggs, creme fraiche, garlic and 1 teaspoon salt in a bowl.
Put the milk in a small saucepan over medium heat. As soon as the edges of the milk start to bubble, remove from the heat. Slowly pour the milk into the egg mixture, whisking at the same time.
Add the remaining butter to the skillet and smear it around to coat. Arrange a layer of potatoes in a concentric circle on the base of the pan. Sprinkle generously with salt and black pepper. Pour 1/3 of the egg mixture over the potatoes and sprinkle with 1/3 of the leeks and cheese. Repeat the layers twice more.
Cover the pan with foil and bake 40 minutes. Stick a small sharp knife down into the center of the potatoes to make sure they're tender. If not, bake 5-10 more minutes. Uncover and bake an additional 25 minutes, until the top is golden and the cheese is bubbling.
Let cool at least 15 minutes before slicing and serving. Sprinkle with parsley.
To make ahead: Prepare the recipe through step 5. Cover and refrigerate up to a day ahead before baking.
Be sure to season the potato layers with plenty of salt for best flavor.