Start by preheating your oven to 400°F (200°C). This step is crucial for getting that golden-brown crust.

In a large mixing bowl, combine the ricotta, mozzarella, and feta cheeses. Add your chopped roasted red peppers, artichokes, and Kalamata olives. If using, stir in the dried oregano and crushed red pepper flakes. Mix well and set aside.

On a lightly floured surface, roll out each ball of pizza dough into a circle about 10 inches in diameter. The dough should be thick enough to hold the filling but not so thick that it becomes doughy.

Place a generous scoop of the cheese and vegetable mixture on one half of the dough circle. Be careful not to overfill—around 1/3 to 1/2 cup should do. Fold the other half over and pinch the edges to seal. Use a fork to crimp the edges, ensuring a tight seal.

Place the calzones on a baking sheet lined with parchment paper. For a shiny finish, you can brush them with a little olive oil. Bake in the preheated oven for 25-30 minutes, or until golden brown.

Remove the calzones from the oven. Allow them to cool for a few minutes before serving. Pair with extra pizza sauce on the side for dipping.