Preheat the oven to 425 degrees F. Spray the cavities of a mini muffin pan with cooking spray.
Remove the pizza dough from the packaging and allow it to come to room temperature on a floured surface.
Using a rolling pin or your hands, roll it out into a VERY thin layer. Using either a small round cookie cutter (about 2 inches) or an empty 4.5-ounce can, cut it into rounds.
Using your fingers, stretch the dough without tearing and press into the prepared muffin cups.
Next, assemble the pizzas. Spoon about 2 teaspoons of the crushed tomatoes into each cup. Sprinkle with a little Italian seasoning and top with about 1 tablespoon of mozzarella. Top with the mushrooms, sausage and pepperoni or whatever toppings you prefer.
Bake until the crust is golden brown and the cheese is melty and bubbly, 15 to 20 minutes.