A food processor is ideal for making the pizza crust, although it can be made by hand. In a small bowl, dissolve the yeast in the warm water. Add the sugar and let stand until foamy, about 5 minutes.

In a food processor bowl fitted with a metal blade, combine the yeast mixture, salt, 1 tablespoon of the olive oil, and 3 cups of the flour. Process until the ingredients come together into a ball. If the dough is too wet, add more flour, a little at a time, until a smooth, firm texture is achieved. Continue to process for 3 to 4 minutes after the ball is formed, or until the dough is smooth and silky but firm. Turn the dough out onto a well-floured board and knead until the dough becomes elastic, 4 or 5 minutes.

If preparing the dough by hand in a bowl, follow the same steps, but use only 2 cups of flour instead of 3 cups to start and work the ingredients together with a fork or your fingertips. Gradually add more flour until the dough forms a stiff ball. Turn the dough ball out onto a well-floured board and knead it until it becomes smooth and elastic. This will take 6 or 7 minutes.

Oil a large bowl with the remaining 1 tablespoon olive oil. Place the dough ball in the bowl and turn the ball to coat the surface with oil. Cover the bowl with a clean cloth and let stand in a warm place until the dough has doubled in size, 1 to 1 1/2 hours. Punch down the dough in the bowl, re-cover it with the cloth, and let it rest for another 30 minutes.

Preheat an oven to 500°F. Divide the dough into 2 or 4 equal portions, depending upon the number of pizzas you are making. On a lightly floured board, roll out each portion into a round 1/8 inch thick. If you are making 2 pizzas, each round should be about 12 inches in diameter. If you are making 4 pizzas, each round should be about 6 inches in diameter. Sprinkle the pizza pans or large baking sheets with the cornmeal and transfer the dough rounds to the pans.

To top the pizzas, drizzle half of the olive oil over the surface of the dough rounds. Divide the tomato slices and olives evenly among the dough rounds. Strew the cheese over the tomato slices and then sprinkle with 2 tablespoons of the rosemary. Cook the pizzas on the upper rack of the oven until the bottom of the crust is crisp and the edges are lightly browned, 10 or 12 minutes.

Remove the pizzas from the oven. Drizzle with the remaining 2 to 2 1/2 tablespoons olive oil, then sprinkle with the remaining 2 tablespoons rosemary. Cut the larger pizzas into wedges and leave the smaller pizzas whole. Serve immediately.