Preheat your oven to 400°F while you gather everything. In a shallow bowl or flat plate, combine the Italian-seasoned breadcrumbs, grated Parmesan, garlic powder, salt, black pepper, and paprika. Mix it all together with a fork until evenly combined—you want the cheese and seasonings distributed throughout so every bite has flavor. Set this aside within arm's reach of your cutting board.

Slice each chicken breast in half lengthwise to create two thin fillets from each breast (you'll end up with 6 pieces total). Place the fillets between two pieces of plastic wrap on a cutting board. Using a meat mallet or the bottom of a heavy skillet, gently pound each piece until it's about ⅜-inch thick. This step is critical—even thickness means even cooking, and it also makes thinner chicken that crisps up beautifully without drying out inside.

Generously brush both sides of each chicken fillet with mayonnaise (or melted butter if you prefer). You want a thin, even coating—this is what makes the breadcrumb mixture stick and creates that gorgeous golden crust. Now, dredge each coated fillet in your breadcrumb mixture, pressing gently so the coating adheres on both sides. Lay each piece on a baking sheet sprayed with cooking spray or lined with parchment paper.

Bake for 17-20 minutes at 400°F until the chicken reaches an internal temperature of 165°F when measured with a meat thermometer at the thickest part. The coating should be golden brown and crispy. If you don't have a thermometer, cut into the thickest piece—no pink should remain inside. Let cool for 2-3 minutes before serving to lock in juices.