Step 1
Slice each chicken breast down the center to make 4 cutlets. Place each between 2 pieces of plastic wrap and pound to about 1/2 inch thinness with a meat mallet.
Step 2
Marinate chicken breasts in Italian dressing in the refrigerator overnight.
Step 3
Remove chicken to bring to room temperature 1 hour before cooking.
Step 4
Combine flour and baking powder in one bowl milk and egg in another bowl and bread crumbs in a third bowl. Set aside.
Step 5
Heat 1 tablespoon butter in a pan over medium heat. Cook prosciutto in the hot butter until it starts to brown about 5 minutes. Transfer to a paper towel-lined plate.
Step 6
Bring marinara sauce to a simmer in a saucepan.
Step 7
Heat oil in a deep-fryer or large saucepan to 375 degrees F (190 degrees C). Preheat the oven to 450 degrees F (230 degrees C).
Step 8
Lay chicken cutlets out flat. Line 1/4 of mozzarella cheese down the center of each and sprinkle 1/4 of prosciutto over cheese. Fold cutlets in half over the stuffing and secure edges together with toothpicks.
Step 9
Dunk rolled chicken into the flour mixture then egg mixture and finally bread crumbs.
Step 9
Drop chicken into the preheated fryer and cook until crumbs are golden brown chicken floats and is no longer pink in the center 6 to 7 minutes. Transfer to a paper towel-lined plate to let grease run off.