01 - Place each chicken breast between two sheets of plastic wrap and pound to an even 1/2-inch thickness using a meat mallet.
02 - Whisk together buttermilk, salt, black pepper, paprika, and garlic powder in a shallow bowl. Add chicken breasts and turn to coat thoroughly. Marinate for 15 minutes to 2 hours.
03 - Arrange three shallow bowls: one with flour, one with beaten eggs mixed with Dijon mustard, and one with panko, Parmesan, and oregano combined.
04 - Remove chicken from marinade, allowing excess to drip off. Dredge each piece in flour, dip in egg mixture, then coat with panko-Parmesan mixture, pressing gently to adhere.
05 - Heat oil in a large skillet over medium-high heat to 350°F. Fry chicken in batches for 3-4 minutes per side until golden brown and internal temperature reaches 165°F.
06 - Transfer to paper towel-lined plate to drain. Let rest 2 minutes before serving.