Butterfly your chicken breasts, then place in a zip-top bag. Using a mallet, or even a small pan, pound each breast until it’s about 1/8 to 1/4 inch thick.
Prepare 3 separate dishes. 1 with flour, one with egg wash (whisk egg with milk), and Italian seasoned bread crumbs, with Parmesan cheese, salt and pepper in another baking dish. Coat each breast in the flour, then egg wash, then liberally coat each side of the breast in the bread crumbs.
Set oven to Broil, and heat your oil to about 350 F. When oil is up to temperature, carefully place chicken breast one at a time in the pan. Cooking about 3-5 minutes per side until internal temperature is 165 F. Place on a cooling rack.
Add fresh mozzarella on top and place in the broiler, about 5 minutes or until mozzarella is bubbly and brown. Heat up your marinara sauce in a pan.
Toast buns, add a heaping spoonful of marinara on the bun. top with a chicken breast (can be cut in half), add more parmesan cheese and basil. Serve and enjoy!