Beef & Cheese Quesadillas

1 pound ground beef
½ cup chopped onion
¾ cup chunky salsa
2 cups shredded Colby jack cheese
10-12 flour tortillas

Brown ground beef with onion. Drain. Mix in salsa and cheese. Spoon ½ cup meat mixture on one half of tortilla. Fold tortilla in half to close. Arrange quesadillas on baking sheet. Lightly spray tops of tortillas with cooking spray. Bake at 450° for 8 minutes or until lightly browned.