Creating the Chicken Parmesan Sandwich is simple and fun. Follow these steps for a delicious result:

1. Prep the Chicken: Place the chicken breasts between two sheets of plastic wrap. Pound them to an even thickness using a meat mallet or rolling pin.
2. Season the Flour: In a shallow dish, mix the flour, salt, black pepper, and garlic powder.
3. Prepare the Egg Wash: In another bowl, beat the eggs until well combined.
4. Set Up the Breading Station: Place the breadcrumbs in a third shallow dish.
5. Bread the Chicken: Dredge each chicken breast in the seasoned flour, shaking off any excess. Dip into the egg wash, then coat with breadcrumbs, pressing gently to adhere.
6. Heat the Oil: In a large skillet, heat about ½ inch of olive oil over medium heat until shimmering.
7. Fry the Chicken: Carefully place the breaded chicken in the hot oil. Cook for 4-5 minutes on each side or until golden brown and cooked through. Remove and drain on paper towels.
8. Preheat the Oven: While the chicken is frying, preheat your oven to 375°F (190°C).
9. Assemble the Sandwiches: Spread marinara sauce on the bottom of each sandwich roll. Place the fried chicken on top, then add more marinara sauce. Sprinkle shredded mozzarella and grated Parmesan cheese over the chicken.
10. Bake the Sandwiches: Place the assembled sandwiches on a baking sheet and bake in the preheated oven for 10-15 minutes, until the cheese is bubbly and golden.
11. Garnish and Serve: Remove from the oven and add fresh basil leaves if desired. Serve immediately and enjoy!