To assemble: prepare Pizza Crust and Marinara Sauce as directed.
Spray pizza pan with non-stick cooking spray or brush with olive oil. Gently stretch Pizza Crust to fit pan, forming raised edge at lip. Sprinkle crust with grated mozzarella cheese.
Dot with browned sausage, ground beef, pepperoni and chopped and sauteed onion. Gently spread Marinara Sauce to cover cheese and toppings. Sprinkle with parmesan cheese and salt to taste.
To freeze: flash freeze pizza in pan. When frozen, wrap in aluminum foil.
To prepare: do not thaw pizza. Heat oven to 400 degrees. Bake frozen pizza for 20 to 25 minutes, until crust is browned, sauce bubbles and cheese is fully melted.