Warm the butter or oil in a large pan. Sauté sliced mushrooms until soft and fragrant, about 8 minutes. Add zucchini, salt, red pepper flakes, pepper, and optional garlic. Sauté another 5 minutes, stirring occasionally.
Place pitas on 1-2 large baking sheets. (Optional: mix the minced garlic with the ricotta cheese.) Spread ricotta cheese on each pita. Top with cooked vegetable mixture.
Bake on 450ºF for about 10-12 minutes. Serve immediately or freeze for later!
Notes
To freeze: let cool completely. Place wax paper on top of each pizza and stack. Place in freezer bags and freeze. Alternately - freeze flat on baking sheet for 1 hour them move to freezer bag. Toppings: start with about 5-6 cups raw vegetables, and up to 1 cup meat.