Preheat the oven and prepare the dough and toppings
Remove the dough from the refrigerator and keep it covered at room temperature. Place the rimmed baking sheet upside down on a lower-middle oven rack and preheat the oven to 475°F for at least 30 minutes. Meanwhile, halve and peel the onion, then slice it 1/8 inch thick. Peel a firm section of the squash neck and use the vegetable peeler to shave 2 loosely packed cups of thin ribbons. Shred the mozzarella and grate the Parmesan. Keep the sage leaves whole and pat them completely dry.
Stabilize the squash on the cutting surface and move the peeler away from your hands and body.


















