1. Preheat oven to 375°.
2. Line a baking sheet with parchment paper. Set aside.
3. Cook 1/2 pound ground sirloin, 1/2 cup chopped onion, 1 teaspoon onion powder, 1 teaspoon garlic powder, 1 teaspoon dried Italian seasoning, and 2 minced garlic cloves in a large nonstick skillet over medium-high heat 5 minutes, stirring to crumble beef. Drain.
4. Cut dough into 4 equal portions. Roll 1 portion into a 6-inch circle on a work surface sprinkled with 1 tablespoon flour. Repeat procedure with remaining dough and flour.
5. Spoon 1/4 cup beef filling into center of each circle; sprinkle each with 1/4 cup cheese. Brush edges of dough with water; fold dough in half over filling, pressing firmly to seal.
6. Place calzones on prepared baking sheet; coat tops with cooking spray. Bake at 375° for 15 minutes or until crust is golden brown. Cool slightly, and serve with warm pizza sauce, if desired.