01 - Preheat oven to 400°F. Lightly grease a large baking dish with cooking spray or a small amount of olive oil.
02 - Place each chicken breast 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 together eggs and milk until combined. In a third bowl, combine breadcrumbs, ½ cup Parmesan cheese, oregano, garlic powder, salt, and pepper.
04 - Dredge each chicken breast in flour, shaking off excess. Dip into egg mixture, allowing excess to drip off. Press firmly into breadcrumb mixture to coat evenly on both 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 brown and crispy. Transfer to paper towel-lined plate to drain.
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, add dried basil and sugar if using. Simmer for 5 minutes.
07 - Spread 1 cup of sauce evenly in the bottom of the prepared baking dish. Arrange fried chicken breasts on top. Spoon remaining sauce over each piece. Sprinkle mozzarella cheese and remaining ½ cup Parmesan cheese evenly over chicken.
08 - Bake uncovered for 18–20 minutes until cheese is bubbly and lightly browned, and chicken reaches 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.