In a large bowl, whisk together 3 cups flour, 2 tsp instant yeast, 1 tsp sugar and 1 tsp salt. Make a well and add 1 cup warm water and 2 tbsp olive oil. Stir until a shaggy dough forms, then turn out onto a lightly floured surface and knead for 6–8 minutes until smooth and elastic. If dough is sticky, add up to 2 tbsp more flour.

First Rise

Lightly oil a clean bowl, place the dough inside, cover with plastic wrap or a damp towel and let rise in a warm place until doubled, about 60–75 minutes.

Portion Dough

Punch down dough and divide into 2 equal portions for two medium calzones. Let the portions rest, covered, for 10 minutes before shaping.

Filling & Sauce

Make the Sauce

Heat 1 tbsp olive oil in a small saucepan over medium heat. Add minced garlic and cook 30–45 seconds until fragrant. Add 1 cup crushed tomatoes (or passata), 1 tsp dried oregano, 1 tsp dried basil, 1 tsp salt and 1/2 tsp black pepper. Simmer gently for 8–10 minutes to slightly thicken. Remove from heat and let cool to warm.

Prep Filling Ingredients

While the sauce simmers, dice 1 cup ripe tomatoes, halve 1/2 cup pitted kalamata olives, thinly slice 1/4 cup red onion, and roughly chop 1 cup baby spinach.

Assemble Filling Mix

In a bowl combine the diced tomatoes, olives, red onion, chopped spinach, 1 cup crumbled feta and 1 cup shredded mozzarella. Spoon in about 1/2 cup of the cooled tomato sauce and gently toss so the filling is moist but not soupy. Taste and adjust salt/pepper if needed (remember feta is salty). Reserve remaining sauce for brushing or serving.

Assembly & Baking

Preheat Oven

Preheat the oven to 475°F (245°C). If using a pizza stone, place it on a rack in the middle of the oven while preheating. Line a baking sheet with parchment if not using a stone.

Shape Dough

On a lightly floured surface, roll each dough portion into a roughly 9–10 inch circle about 1/8–1/4 inch thick.

Fill Calzones

Place half of the filling mixture on one semicircle of each rolled dough, leaving a 1-inch border around the edge. Spoon an additional 1–2 tbsp of reserved sauce on top of the filling if desired. Do not overfill to avoid leaking.

Seal and Crimp

Brush the exposed border with a little water, fold the dough over to make a half-moon and press edges to seal. Crimp the edge by folding and pinching or using a fork to press all the way around.

Egg Wash & Season

Brush each calzone with the beaten egg, then brush lightly with 1 tsp olive oil and sprinkle 1/2 tsp dried oregano divided between the two. Make two or three small steam vents on top with the tip of a knife.

Bake

Transfer calzones to the preheated stone or baking sheet. Bake for 12–16 minutes until golden brown and puffed, rotating halfway if needed for even color. Internal temperature should be about 200°F (93°C) when done.

Rest & Serve

Let calzones rest on a rack for 5 minutes to set the filling. Serve warm with remaining sauce on the side for dipping.