Spinach and Red-Pepper Calzones

Ingredients

• 8 cups baby spinach packed
• 1.5 tablespoons cornmeal 
• 2  garlic clove finely chopped
• 0.5 pound mozzarella cheese smoked cut into 16 pieces
• 3 tablespoons olives black pitted coarsely chopped
• 3 tablespoons olive oil extra virgin extra-virgin divided
• 1 large onion halved sliced lengthwise
• 1 pound pizza dough thawed store-bought
• 4  roasted peppers red dry rinsed cut into 1-inch pieces (1 cup)

Equipment

• frying pan
• baking sheet
• oven
• rolling pin

Directions

1. Preheat oven to 500°F with rack in lowest position.
2. Sprinkle cornmeal on a large baking sheet.
3. Cook onion with 1/4 teaspoon salt in 2 tablespoons oil in a large heavy skillet over medium heat, stirring occasionally, until beginning to brown, 8 to 10 minutes.
4. Add garlic and cook until fragrant, about1 minute.
5. Add spinach and cook, stirring frequently, until wilted, about 2 minutes. Stir in red peppers, olives, and pepper to taste.
6. Remove from heat.
7. Roll out dough on a lightly floured surface with a lightly floured rolling pin into a 14-inch round, then cut into quarters.
8. Roll out 1 quarter into an 8-inch square (keep remaining pieces covered) and arrange with a corner nearest you. Put one fourth of filling on lower half, leaving a 1-inch border, and top with 4 pieces of cheese. Fold dough over to enclose filling. Seal edges. Beginning in 1 corner, stretch sealed edge outward, pinching and rolling dough up over edge to resemble a rope, working your way around.
9. Transfer to baking sheet. Make 3 more calzones in same manner.
10. Cut 3 steam vents in top of each and brush with remaining tablespoon oil.
11. Bake until golden-brown, 13 to 15 minutes. Cool 5 minutes before serving.
12. Filling (without cheese) can be made 1 day ahead and chilled. Bring to room temperature before using.