This Irresistible Scalloped Potato Recipe Gives You a Pan Full of the Best Part

Recipe View Preheat oven to 450°F (230°C). Grease the bottom and sides of an 18x13-inch sheet pan with 1 tablespoon of the softened butter. (5 minutes)

Recipe View Melt remaining 2 tablespoons butter in a large nonstick skillet over medium heat. Add thinly sliced yellow onions, cover, and cook, stirring occasionally, until softened and translucent. (5-7 minutes)

Recipe View Reduce heat to medium-low, uncover, and continue cooking, stirring occasionally, until the onions are deeply caramelized and brown. (30-35 minutes)

Recipe View While the onions are caramelizing, in a small saucepan, combine heavy whipping cream, thinly sliced garlic, fresh thyme leaves, chopped fresh rosemary, black pepper, and 1/2 teaspoon kosher salt. Bring to a simmer over medium heat, then immediately remove from heat. (10 minutes)

Recipe View Using a mandoline or a very sharp knife, thinly slice Yukon Gold potatoes into 1/8-inch-thick rounds. (10 minutes)

Recipe View Arrange half of the potato slices (about 3 1/2 cups) in a single, overlapping layer on the prepared baking sheet, ensuring the bottom of the sheet is covered. (5 minutes)

Recipe View Sprinkle evenly with 1 teaspoon kosher salt, the caramelized onions, and 1/3 cup finely shredded Parmesan cheese. (2 minutes)

Recipe View Top with remaining potato slices in a single overlapping layer, and sprinkle with the remaining 1 teaspoon kosher salt. (5 minutes)

Recipe View Pour the hot cream mixture evenly over the potatoes, ensuring they are well-covered. Cover the baking sheet tightly with aluminum foil. (2 minutes)

Recipe View Bake in the preheated oven until the potatoes are tender when pierced with a fork. (20-25 minutes)

Recipe View Carefully remove the foil, scraping off any potato or garlic slices that may be stuck to it. Sprinkle the potatoes with the shredded extra-sharp white Cheddar cheese and the remaining 1/3 cup finely shredded Parmesan cheese. (2 minutes)

Recipe View Return to the oven and bake, uncovered, until the top is browned and crusty, rotating the pan halfway through. (15-20 minutes)

Recipe View Sprinkle with more fresh thyme leaves for garnish and serve immediately. Enjoy! (1 minute)