Cooking with Giada: The secrets to great pizza

In a large pot, heat the oil over a medium-high flame. Add the onions and garlic and sauté until the onions are translucent, about 10 minutes. Add the celery, carrots, and 1/2 teaspoon each of salt and pepper. Sauté until all the vegetables are soft, about 10 minutes. Add the tomatoes and bay leaves, and simmer uncovered over low heat until the sauce thickens, about 1 hour. Remove and discard the bay leaves. Season the sauce with more salt and pepper to taste. (The sauce can be made 1 day ahead. Cool, then cover and refrigerate. Rewarm over medium heat before using.)

Mix the warm water and yeast in a small bowl to blend. Let stand until the yeast dissolves, about 5 minutes. Mix the flour and salt in a food processor to blend. Blend in the oil. With the machine running, add the yeast mixture and blend just until the dough forms. Turn the dough out onto lightly floured surface and knead until smooth, about 1 minute. Transfer the dough to a large oiled bowl and turn the dough to coat with the oil. Cover the bowl with plastic wrap and set aside in a warm draft-free area until the dough doubles in volume, about 1 hour. Punch the down dough and form into ball. (The dough can be used immediately or stored airtight in the refrigerator for 1 day.)

Position one oven rack in the center and the second rack on the bottom of the oven and preheat to 450 degrees F. Sprinkle the cornmeal over 2 rimless baking sheets. Roll out each piece of pizza dough into a 10- to 11-inch round. Transfer 1 dough to each prepared baking sheet.

Spoon the marinara sauce over the dough, dividing equaling and leaving a 1-inch border around each pizza. Sprinkle the cheeses over the sauce. Bake the pizzas until the crusts are crisp and brown on the bottom and the cheese is melted on top, rotating the baking sheets half way through baking, about 15 minutes. Lay the prosciutto slices over the pizzas, if using. Sprinkle the basil over the pizzas, then cut into wedges and serve immediately.