Sheet-Pan Scalloped Potatoes Recipe | Valerie Bertinelli | Food Network

Ingredients

• 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