Fully baked crustless pizza can be frozen for up to 4 months in an airtight freezer container. For best results, add cheese after baking but before freezing so the cheese doesn't bake twice. To bake frozen crustless pizza: bake it in an unpreheated oven at 400 degrees Fahrenheit for 20 minutes or until fully warmed through. While the oven is preheating, it will gently thaw the pizza.