Preheat the oven to 425 degrees Fahrenheit and line a baking sheet with parchment paper.
Divide the pizza dough evenly into 4 different sections. Roll out each section into a dough circle with a rolling pin that’s approximately ¼ inch thick. Place them on the prepared baking sheet.
Spread the pizza sauce onto half of the dough making sure to leave room around the edges to seal the calzone.
Sprinkle the onions and bell peppers evenly on top of the sauce. Layer 6 pepperonis onto each calzone and evenly sprinkle the shredded cheese on top.
Rub a small amount of water onto the outside edge of the dough. Fold the dough over the topping and crimp the edges shut with either your fingers or a fork.
Gently make 3 slices on top of each calzone to allow air to escape while cooking.
Rub the olive oil on top with a basting brush. Sprinkle the parmesan cheese and Italian seasoning on top.
Bake for 12-14 minutes until golden brown.
Serve warm and enjoy!
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Notes
If you use pizza dough that comes in the sheet form, use a sharp knife to cut out the circles instead of rolling it out again. Make sure that the edges are sealed tightly. The water helps form a tight seal to prevent it from coming apart while cooking it. These are best served fresh but the leftovers can be stored for up to 5 days as long as they are refrigerated in an airtight container.I recommend reheating them in the oven to make the outside crispy again.