1. Preheat oven to 220C. Place two large baking trays in preheated oven to heat while preparing pizzas - at least 5 minutes.
2. Spread 1 tablespoon tomato passata over each pita bread. Top each with a quarter of the ham, zucchini and tomatoes. Crumble 2 tablespoons ricotta over each pizza and dot each with 1 1/2 teaspoons pesto. Place pizzas on preheated trays and bake for 10 minutes or until base is crisp.
3. To serve, cut each pizza into quarters and serve immediately.