Sheet-Pan Scalloped Potatoes
This recipe creates a rich and creamy sheet-pan scalloped potato dish, perfect as a hearty side. Thinly sliced Yukon Gold potatoes are layered with caramelized onions, Fontina, and Parmesan cheese, then baked in a rosemary-Dijon-lemon infused heavy cream until golden, tender, and bubbly.
Equipment
- 1 Large Rimmed Baking Sheet (18x13 inches)
- 1 Large Saute Pan
- 1 Mandoline Slicer or Sharp Chef's Knife For consistent potato slices
- 1 Box Grater For Fontina and Parmesan cheeses
- 1 Aluminum Foil
Ingredients
Main
- Canola spray for the baking sheet
- 2 tablespoons unsalted butter
- 1 1/2 cups thinly sliced yellow onion 1 large onion
- 1 tablespoon minced garlic 2 to 3 cloves
- 3 1/4 pounds medium Yukon Gold potatoes 6 to 7 potatoes, cut into 1/8-inch rounds
- Kosher salt and freshly ground black pepper
- 1 1/2 cups grated fontina cheese about 8 ounces
- 1 cup grated Parmesan about 5 ounces
- 2 cups heavy cream
- 2 tablespoons finely chopped fresh rosemary
- 1 tablespoon Dijon mustard
- 1 teaspoon lemon zest
Instructions
- Preheat the oven to 450 degrees F. Spray a large, rimmed baking sheet (18-by-13 inches).
- Melt the butter in a large sauté pan over medium heat. Add the onions and cook, stirring occasionally, until lightly caramelized, 15 to 20 minutes; if the onions are browning too quickly, reduce the heat to low. When the onions are almost done, stir in the garlic and cook an additional 2 minutes to lightly toast. Remove from the heat.
- Shingle half of the potatoes in 6 or 7 even rows on the prepared baking sheet, making sure the sheet is completely covered. Season the potatoes with salt and pepper, and sprinkle with half of the fontina and Parmesan. Next, evenly spread the caramelized onions over the top; place the sauté pan back on the stovetop and reserve for later. Shingle the remaining half of the potatoes over the onions, and season with more salt and pepper.
- Turn the heat to medium under the sauté pan. Add the cream, rosemary, Dijon and lemon zest, stir together and bring to a simmer. Season with salt and then pour the cream over the potatoes; tilt the baking sheet slightly in all directions to ensure even coverage. Top with the remaining fontina and Parmesan.
- Cover the baking sheet with foil and bake for 15 minutes. Remove the foil and continue baking until the top is golden brown, the edges are crispy and the potatoes are tender, another 20 to 25 minutes. Let the cool for 15 minutes before serving.
Notes
Achieving perfectly tender scalloped potatoes with a crisp top relies on consistent potato thickness, ideally 1/8-inch, which is best done with a mandoline. For the onions, truly caramelizing them slowly over medium-low heat is crucial for deep flavor – patience here pays off. When adding the cream mixture, ensure it's just at a simmer, not a rolling boil, to prevent scorching and ensure it thickens properly as it bakes. Tilting the baking sheet gently helps distribute the cream evenly. Don't skip the resting period after baking; it allows the cheese and cream to set, preventing the potatoes from falling apart when served. A pinch of freshly grated nutmeg in the cream mixture can further enhance the classic gratin flavor profile.