Broccoli Calzones

From : http://www.yummly.com/recipe/external/Broccoli-Calzones-Martha-Stewart
PREP: 1 hour 
TOTAL TIME: 1 hour 30 mins
SERVINGS:8

INGREDIENTS

1 tablespoon olive oil 
2 packages (10 ounces each) frozen chopped broccoli, 
thawed 
4 garlic cloves, 
chopped 1/4 teaspoon red-pepper flakes Flour, 
for rolling dough 2 packages (1 pound each) balls fresh or frozen pizza dough, thawed if frozen 
1 cup part-skim ricotta cheese 
1/2 cup grated Parmesan cheese 
1 1/2 cups shredded (6 ounces) part-skim mozzarella cheese 
Coarse salt and ground pepper 
Prepared tomato sauce (optional) 
1 medium red onion, finely chopped

COOK'S NOTE

To freeze: Prepare recipe through step 3. Tightly wrap each calzone in plastic; freeze until firm. Transfer calzones to resealable plastic bags; label and date. Freeze up to 2 months. To serve, unwrap calzones, and place on parchment-lined baking sheets; bake without thawing until golden, 35 to 40 minutes.

DIRECTIONS

STEP 1
In a large nonstick skillet, heat oil over medium. Add onion; cook until softened, 4 to 5 minutes. Add broccoli, garlic, and pepper flakes. Cook, stirring occasionally, until liquid has evaporated, 5 to 7 minutes. Transfer to a medium bowl; set aside to cool.
STEP 2
Preheat oven to 400 degrees. Form calzones: Divide dough into 8 equal pieces. On a lightly floured surface, stretch each piece out, first to a 3-by-4-inch oval, then stretch again, this time to a 6-by-8-inch oval. (Let dough rest a few minutes if too elastic to work with.)
STEP 3
Stir cheeses into cooled broccoli mixture; season generously with salt and pepper. Assemble calzones: Spread a rounded 1/2 cup broccoli mixture over half of each piece of dough, leaving a 1/2-inch border; fold over to form a half-moon. Press edges to seal. With a paring knife, cut 2 slits in the top of each calzone.
STEP 4
Using a wide metal spatula with a thin blade, transfer calzones to 2 baking sheets lined with parchment or waxed paper; reshape if needed.
STEP 5
Bake until golden, about 25 minutes. Serve with tomato sauce, if desired.