01 - Preheat oven to 400°F. Lightly grease a large baking dish with cooking spray or a small amount of olive oil.
02 - Place chicken breasts between two sheets of plastic wrap. Using a meat mallet or rolling pin, pound to an even ½-inch thickness for uniform cooking.
03 - Place flour in one shallow bowl. In a second bowl, whisk eggs with milk. In a third bowl, combine breadcrumbs, ½ cup Parmesan, oregano, garlic powder, salt, and pepper.
04 - Dredge each chicken breast in flour, shaking off excess. Dip in egg mixture, allowing excess to drip off. Press firmly into breadcrumb mixture to coat thoroughly on all sides.
05 - Heat 4 tablespoons olive oil in a large skillet over medium-high heat. Fry chicken breasts for 2–3 minutes per side until golden and crisp. Transfer to a paper towel-lined plate. Chicken will finish cooking in the oven.
06 - In a saucepan, heat 1 tablespoon olive oil over medium heat. Add minced garlic and sauté for 30 seconds until fragrant. Pour in marinara sauce, dried basil, and sugar if using. Simmer for 5 minutes.
07 - Spread 1 cup of sauce in the bottom of the prepared baking dish. Arrange fried chicken breasts on top. Spoon remaining sauce evenly over each piece. Sprinkle with mozzarella and remaining ½ cup Parmesan.
08 - Bake uncovered for 18–20 minutes, or until cheese is bubbling and lightly browned. Chicken should reach an internal temperature of 165°F.
09 - Remove from oven and let rest for 5 minutes. Garnish with chopped fresh basil or parsley. Serve immediately while hot.