Preheat and prep the pan. Set your oven to 450°F (232°C). Line a baking sheet with parchment. Sprinkle with a little semolina or cornmeal to help crisp the bottoms.

Bring the dough to room temperature. If you’re using refrigerated or store-bought dough, let it sit for 30–45 minutes. This makes it easier to stretch and reduces bounce-back.

Cook the vegetables. Heat olive oil in a large skillet over medium heat. Add onion, bell pepper, zucchini, and mushrooms with a pinch of salt. Cook until the veggies release moisture and start to brown, about 6–8 minutes.

Add aromatics and greens. Stir in garlic, Italian seasoning, and crushed red pepper flakes. Cook 30 seconds until fragrant. Add spinach and cook until wilted. Taste and season with salt and pepper. Remove from heat and cool for 5 minutes.

Mix the cheeses. In a bowl, combine ricotta, mozzarella, and Parmesan. Add a pinch of salt and pepper. For extra flavor, you can mix in a spoonful of pesto or chopped fresh basil.

Divide the dough. Cut the dough into 4 equal pieces for large calzones, or 6 for smaller ones. Dust your work surface with flour. Press each piece into a round, then gently stretch to about 7–8 inches in diameter.

Fill the calzones. Spread a layer of cheese mixture on one half of each dough round, leaving a 1-inch border. Spoon on the cooled vegetables. Don’t overfill—about 1/2 cup veggies per large calzone is plenty.

Seal well. Fold the empty side of the dough over the filling to form a half-moon. Press the edges to seal. Fold the edge up and over itself, then crimp with your fingers or a fork. Make 2–3 small slits on top for steam to escape.

Egg wash and bake. Brush the tops with egg wash for shine and color. Transfer to the baking sheet and bake 14–18 minutes, until golden brown and puffed. Rotate the pan once for even browning.

Rest and serve. Let the calzones cool for 5 minutes. Serve with warm marinara for dipping. A sprinkle of Parmesan and a drizzle of olive oil on top is a nice finish.