To begin, finely chop red bell pepper, green onions, garlic and celery, set aside. If you prefer your veggies smaller, you can pulse them in a food processor to achieve desired texture. In a small bowl, whisk one large egg. Peel and devein shrimp. I like to use large shrimp because they are easier to peel and devein. Roughly chop shrimp or pulse in food processor 3-4 times to desired consistency. To achieve the best texture for the burger, I like to chop my shrimp into various sizes but it is up to you. In a large mixing bowl, combine finely chopped vegetables. Add lemon juice, Dijon mustard, Worcestershire sauce, and whisked egg. Stir to combine. Add shrimp, Old Bay, and salt & pepper to the mixture. Stir to combine. Fold in panko bread crumbs, add more panko if needed. Form into 5 evenly sized balls, approximately the size of a tennis ball. Gently press down to form patties. Place patties on a sheet pan and refrigerate for 20-30 minutes. This allows the patties to firm up.