Preheat oven to 450F.
Put ground beef into a big bowl. Put onion and celery into food processor. Follow with the green pepper after you deseed it and cut it into chunks. Pulse on finely chopped. Add to bowl when done.
Add egg, bread crumbs, and grill seasoning to bowl.
Next, mix bbq sauce, salsa, and Worcestershire sauce in a small bowl. Pour half in meatloaf mixture and mix with clean hands.
Brush oil over the 12-muffin tin. Use an ice cream scoop to help fill meat in each tin. Top each meatloaf with a spoonfull or more of the bbq sauce.
Bake for 20 minutes. Cut one open to make sure it's done.