At least one hour prior to baking the chicken, marinate in one cup of buttermilk. Refrigerate until baking.
Preheat the oven to 425°F and spritz a baking sheet with cooking spray. Remove the chicken from the buttermilk marinade, and discard. Cut a slit in each chicken breast to form the pocket for the cheese being careful not to cut all the way through. Insert a folded slice of thick cut provolone cheese into the pocket. Of course, you could use your favorite cheese, if you like. Repeat this process with all of the chicken breasts.
To prepare the dredging ingredients, mix one beaten egg with 3 tablespoons of milk, set aside. Season 1 cup of all purpose flour with 1/2 tsp each of salt, paprika and black pepper. [or to your taste] This amount of flour is likely more than needed. I prefer make a little extra, than not have enough. For the breading, mix together the bread crumbs, grated Parmesan-Romano, dried parsley, garlic powder and salt. Prepare the dredging ingredients in this order. Seasoned flour, egg wash, bread crumb coating. Have your baking sheet nearby so, you can move the chicken directly onto the pan after coating.
After dredging, place the chicken breasts onto the baking sheet, and secure each one with toothpicks. [tip: Dip the toothpicks in water so, they won't get too hot in the oven] If you have long skewers, you could use those instead to skewer along the sides of the chicken to secure the pocket. Drizzle each piece with melted butter or margarine.
Place into the oven and bake for 25 minutes. Depending on the thickness of your chicken breasts, this may take a few minutes longer, or if they're thinner, less time. Rule of thumb with chicken is to bake until the juices run clear. Very important!
Allow the chicken breasts to rest on the pan 5-10 minutes before serving. This chicken can be eaten alone, or with a dipping sauce such as marinara sauce. Yield: 4 pieces.