Preheat oven to 350°. In a large skillet, cook beef and onion over medium heat 6-8 minutes or until beef is no longer pink, breaking up beef into crumbles; drain. Stir in broccoli, cheese, sour cream, salt and pepper; heat through.
Unroll 1 tube of crescent dough onto a greased baking sheet; form into a 12x8-in. rectangle, pressing perforations to seal. Spoon half of the beef mixture lengthwise down centre of rectangle.
On each long side, cut 1-in.-wide strips at an angle, about 3 in. into the centre. Fold 1 strip from each side over filling and pinch ends together; repeat.
Repeat with remaining ingredients to make second braid. Bake 15-20 minutes or until golden brown.