Preheat oven to 375 degrees F (190 degrees C).Advertisement
Cook and stir ground beef in a large skillet over medium heat until browned and crumbly, about 10 minutes; drain excess grease.
Stir broccoli, mozzarella cheese, onion, sour cream, salt, and black pepper into ground beef. Bring mixture to a boil, reduce heat to low, and simmer for 10 minutes.
Divide each package of crescent rolls in half to make 4 squares; press perforations to seal each piece into a solid sheet of dough. Place dough squares onto an ungreased baking sheet and gently form each piece into a rectangle. Spoon 1/4 of meat mixture into the center of each rectangle, bring 2 opposite long edges together in the center, and overlap. Pinch edges of dough to seal into filled packets. Brush with beaten egg.
Bake until packets are deep golden brown and the filling is hot, 18 to 22 minutes.
Reynolds® Aluminum foil can be used to keep food moist, cook it evenly, and make clean-up easier.