Slice the baby Bella mushrooms and heat olive oil and butter in a skillet. Sauté the mushrooms for 7-8 minutes until tender.

In a mixing bowl, combine ricotta cheese, Italian seasoning, salt, black pepper, and red pepper flakes. Stir until well blended.

Preheat your oven to 425°F (220°C).

Divide the pizza dough into four sections. Roll each into a circle about ¼-inch thick.

Spread pizza sauce on one half of the rolled dough. Add ricotta filling, pepperoni, sautéed mushrooms, and mozzarella cheese.

Fold the dough over the filling to create a half-moon shape. Press and crimp edges to seal.

Place calzones on a baking sheet. Slice slits on top, brush with olive oil, and bake for 20-22 minutes.

Remove from the oven and let cool slightly before serving.