Cook the pizza bases on an oiled baking sheet for about 3 minutes, until edges begin to brown and crisp.
Spread each pizza base with tomato pasta sauce and divide the remaining ingredients (except oregano leaves) between them, finishing with the prosciutto and peperoni so that they crisp up a little in the oven.
Cook the pizzas for 5 minutes, or until the cheese is melted and the crust is crisp. Remove from the oven, drizzle with a little extra virgin olive oil and scatter with oregano leaves.