Arrange oven racks in the lower and upper third of the oven. Heat oven to 475°F. Roll out dough on a well-floured surface to make two 12-inch squares or rounds, and transfer to two ungreased baking sheets. Top both squares with chopped tomatoes, mushrooms, and black olives. Drizzle with the oil and season with salt and pepper. Bake pizzas for 10 minutes, remove from the oven, and top with the mozzarella. Return to the oven and continue baking 3 to 5 minutes longer, or until the cheese is melted and the edges of pies are lightly browned.