Coat 2 large nonstick baking sheets with nonstick cooking spray.
Place a large nonstick skillet over medium heat. Add sausage and cook for 6 minutes or until no longer pink, stirring to break up sausage.
Add garlic and red pepper flakes and cook and stir 30 seconds. Transfer to a plate lined with paper towels to drain. Let cool completely.
In a medium bowl combine ricotta, Italian cheese blend, egg yolk, spinach and salt and pepper to taste. Cover and refrigerate until ready to use.
Cut dough into 4 pieces. On a lightly floured surface, roll each piece into an 8-inch round. Place rounds on baking sheets. Evenly spoon cheese mixture on half of each round, leaving a 1-inch border. Top evenly with sausage. Top each with 1/4 cup marinara.
Fold dough over filling until edges almost meet. Bring bottom edge over top edge, and crimp edges to seal. Prick the tops with a fork to vent steam.
Bake 12 – 15 minutes or until lightly browned.
Serve with additional marinara, if desired. Serve warm.