Preheat the oven to 450. In food processor combine basil leaves, garlic, olive oil, 1/4 cup of cheese and the salt and pepper. Process, scraping the bowl down once or twice, until the mixture is fairly smooth, about 3 minutes. Spread the pesto over the pizza crusts. Sprinkle the remaining 1/4 cup cheese over the pizzas. Bake about 8 minutes, until the crust is brown and the cheese melts. Cut into 8 wedges and serve hot.