In a large mixing bowl, lightly whisk the egg. Incorporate the salt, freshly ground pepper, garlic powder, rosemary, parsley, Dijon mustard, ketchup, and beef bouillon, stirring until thoroughly combined. Add the finely chopped celery, onion, and Cheddar cheese to the mixture, blending well. Introduce the ground beef, sweet red pepper, and bread crumbs, ensuring all ingredients are evenly integrated.