Preheat oven to 375°F. Lightly grease a 9x13 baking dish.
Coat the chicken: Pour a little Parmesan Garlic sauce into the baking dish. Dip each cutlet into the sauce to coat both sides, then lay them in the pan. Pour the rest of the sauce evenly over the chicken.
Add cheese: Sprinkle grated Parmesan evenly over the sauced chicken. Place a slice of mozzarella on top of each cutlet (if using).
Breadcrumb topping: In a small bowl, mix the seasoned Panko with melted butter. Sprinkle evenly over the chicken and cheese.
Bake covered: Cover loosely with foil and bake for 35 minutes.
Uncover & finish: Remove foil and bake for another 15 minutes, or until chicken reaches 165°F and topping is golden brown.
Optional broil: Broil 1–2 minutes at the end for extra crispiness (watch closely!).
Rest & serve: Let rest 5 minutes before serving. Garnish with extra Parmesan and parsley if desired.
Baking it covered first helps everything cook through, and uncovering at the end gives you that golden, bubbly top.