Unfold piecrusts; stack piecrusts, and press together.
Place piecrust on a parchment-lined baking sheet; spread spaghetti meat sauce evenly over crust, leaving a 1-inch border; top with pepperoni slices. Fold crust edges slightly over filling.
Bake on lower rack at 425 for 15 minutes.
Sprinkle with cheese, and bake 15 more minutes or until bubbly and golden.