Preheat oven to 375°F. Generously coat twelve 3 1/4-inch or 2 1/2-inch muffin cups with cooking spray
On a lightly floured surface, roll pizza dough into a 12x10-inch rectangle. Spread 1/2 cup pizza sauce over the dough. Sprinkle with 1 cup of the cheese, the turkey, sweet pepper, and red onion.
Starting from a long side, roll up dough. Pinch to seal seams. Using a serrated knife, slice roll into 12 equal pieces. Place pieces, cut sides up, in prepared muffin cups.
Bake about 20 minutes or until golden and cheese is melted. Cool in muffin cups on a wire rack at least 10 minutes. Remove stromboli cups from muffin cups. If desired, serve with additional pizza sauce, Parmesan, and/or crushed red pepper.
Refrigerated pizza dough is the time saver. Look for it in tubes or bagged in the deli section of some markets.