In a mixing bowl, blend the egg, egg white, and Dijon mustard. Whisk the ingredients thoroughly. This will create a sticky coating that will allow the breading to form a nice batter-like crust on the chicken.
To make the breading, place the melba toast, thyme, rosemary, oregano, garlic powder, black pepper, salt, and cayenne pepper in a food processor and grind away, but avoid grinding the ingredients down to a fine powder.
Place the breading on a plate. Dip the chicken breasts in the egg mixture, place them into the breading and coat the chicken in the mixture. If you want extra crispy chicken, double dip the chicken in the breading.
Place the chicken-breasts onto a baking tin and spray them lightly with Pam. Place the tin into a 400-degree preheated oven and bake for 15 to 17 minutes. Take them out, flip them over, lightly spray again with Pam, and stick them back in the oven for another 15 to 17 minutes. There should be no pink when you cut through the middle of the breast.