• Preheat oven to 450°.
• Slice each of the boneless, skinless chicken breasts in half horizontally. Cover with plastic wrap and use a meat tenderizer to pound to an even thickness, about ¼" thick.
• Prepare 3 shallow bowls. One with the cornstarch, one with the eggs, and one with both the bread crumbs and the parmesan cheese.
• Coat the chicken on each side with each of the mixtures, starting with the cornstarch, then the eggs, and then the breading/cheese mixture. Repeat a second time.
• Melt the butter in a saucepan with olive oil. Working in batches if needed, add the chicken and fry for about 5 minutes per side until crispy.
• Spray a baking dish with nonstick cooking spray and add the chicken. Top with the shredded mozzarella cheese.
• Bake for 5-10 minutes until the cheese is melted and the chicken is cooked through.

Make the Homemade Marinara:

• Heat the olive oil in a large pot. Add the chopped onion and saute 5 minutes until soft. Add the minced garlic and saute an additional minute.
• Stir in tomato sauce, tomato paste, vinegar, brown sugar, salt and pepper, and dry red wine. Add the red pepper flakes if using. Bring to a boil and then simmer on low until ready to use.