In a large shallow dish, whisk together the eggs, minced garlic, parsley, salt, black pepper, and onion powder.
Add the chicken fillets and turn each piece until completely coated in the egg mixture. Cover and refrigerate for at least 15 minutes. For deeper flavor, the chicken can marinate for several hours.
While the chicken marinates, prepare the tomato sauce. Heat 1 tablespoon olive oil in a medium saucepan over medium heat.
Add the chopped onion and cook for approximately 3 minutes, or until softened and translucent.
Add the minced garlic and cook for about 30 seconds, stirring continuously until fragrant.
Stir in the tomato puree, salt, black pepper, dried Italian herbs, and optional sugar.
Cover partially and simmer the sauce over low to medium-low heat for approximately 8 minutes, stirring occasionally, until slightly thickened. Taste and adjust the seasonings.
Preheat the oven to 430°F (220°C). Lightly grease a large baking dish or rimmed baking sheet.
In another shallow dish, combine the panko breadcrumbs, traditional breadcrumbs, freshly grated Parmesan, and garlic powder.
Remove one chicken fillet at a time from the egg mixture, allowing excess liquid to drip away. Press both sides firmly into the breadcrumb mixture until completely coated.
Heat enough olive oil to generously cover the bottom of a large skillet over medium to medium-high heat.
Working in batches, fry the breaded chicken for approximately 4–5 minutes per side, adjusting the heat as necessary, until the coating is crisp and deeply golden.
Transfer the browned chicken cutlets to the prepared baking dish.
Spoon approximately ⅓ cup tomato sauce over each piece of Crispy Chicken Parmesan, concentrating the sauce toward the center so some crispy edges remain exposed.
Top each cutlet with mozzarella followed by freshly shredded Parmesan. Sprinkle with some fresh basil or parsley.
Bake for approximately 15–20 minutes, or until the mozzarella is melted and bubbling and the thickest part of the chicken reaches 165°F (74°C).
Remove from the oven and let the chicken rest for a few minutes.
Finish with additional fresh basil or parsley and serve warm.