Preheat oven to 350°.
Combine the egg, Worcestershire sauce, lemon juice, seafood seasoning, Dijon mustard, and mayonnaise in a bowl.
Place the crab meat, parsley, and Ritz crackers into a separate bowl. Mix very lightly to combine.
Add the wet ingredients to the crab mixture and combine lightly.
Carefully use a knife to make a “pocket” in each chicken breast for the crab stuffing. Portion a mound of crab filling in the middle of each pocket and fold over to close.
If desired, add stuffed breasts to preheated grill pan to mark exterior before baking.
Place stuffed breasts into a casserole dish or deep baking pan.
Season to your liking with seasoned flour and pour melted butter over top of each chicken breast.
Bake at 350° for 20-25 minutes, or until chicken is cooked to an internal temperature of 165°.