Heat the oven: Heat the oven to 400 F and line a baking sheet or sheet pan with parchment if you want easier cleanup.

Toast the muffin bases: Arrange the English muffin halves cut-side up on the baking sheet, brush them lightly with olive oil, and toast for 5 minutes.

Cool the bases: Let the muffin halves cool completely on a rack so steam does not get trapped under the toppings.

Add the toppings: Spread each muffin half with a spoonful of pizza sauce, then top with mozzarella and a little Parmesan if using.

Freeze until firm: Freeze the mini pizzas on a parchment-lined tray until solid, about 2 hours.

Bag for storage: Transfer the frozen pizzas to a freezer bag or container and keep them frozen for up to 2 months.

Bake from frozen: When ready to eat, heat the oven to 425 F and bake the pizzas straight from frozen for 10 to 12 minutes, until the cheese is melted and the edges are crisp.

Finish and serve: Sprinkle with oregano or red-pepper flakes if you like and serve right away.