In large skillet, cook ground beef and onion over medium heat for 8 to 10 minutes or until browned. Drain well.
Stir in pasta sauce and simmer 5 minutes or until thickened.
Open the crescent rolls and separate the triangles. Place them in a 9" pie plate with the pointed tips facing outward. Using your fingers, press the seams and the open spots of the crescents to create a crust.
Fill the crust with the beef mixture. Add half the cheese. Fold over the tips of the crescent rolls and top with remaining cheese.
Bake for 18 to 20 minutes or until golden brown. Cool 5 minutes before cutting.