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.
Cool 5 minutes. Cut into wedges.