Cook red peppers, onion and leek in chicken broth until tender. Remove and let cool.
Spread 2 tablespoons tomato sauce in each half of pita bread. Place zucchini with cheese (save some cheese for the top) on top leaving the center empty. Place mushrooms and rest of vegetables in the center of each half. Cover with cheese and sprinkle garlic. Season with salt and pepper.
.Place pizza on a baking pan and take to oven 350°F (180°C) for 10 minutes or until golden and cheese melts.