Cooking method:

1. Grease inside of Slow cooker with nonstick cooking spray.
2. Arrange pork tenderloin in slow cooker.
3. Pour over barbecue sauce,stir in thawed chopped onions.Stir well.
4. Cover slow cooker and cook on low-heat setting for 7-9 hours.
5. Using a tongs,remove cooked meat from slow cooker.
6. Transfer into cutting board.
7. Using a two forks
8. Return meat to slow cooker and toss with barbecue sauce until well coated.
9. Heat through.
10. Serve on whole wheat buns with additional barbecue sauce if desired.