On a flat surface, slice each chicken breast in half horizontally, if they are large. Cover the chicken breasts with plastic wrap and pound lightly on the thick end so they are roughly an even thickness. Season generously with salt and pepper, then place in a bowl or Ziploc bag and cover with the buttermilk. Marinate for at least 30 minutes or overnight.
4 small chicken breasts, Salt & pepper, 1 cup buttermilk
Create a breading station by lining up 3 bowls with the flour, powdered sugar, salt, and pepper, in one bowl, eggs in a second, and panko, paprika, garlic powder, and onion powder in the third. You may want to add a little additional salt and pepper to season the breadcrumb mixture or add cayenne pepper or smoked hot paprika for a spicy chicken sandwich.
3/4 cup all-purpose flour, 2 tablespoons powdered sugar, 1 teaspoon Kosher salt, 1 teaspoon black pepper, 2 large eggs, 3/4 cup panko breadcrumbs, 1/2 teaspoon paprika, 1/2 teaspoon garlic powder, 1/2 teaspoon onion powder, 1-2 teaspoons cayenne pepper or smoked hot paprika
Remove the chicken from the buttermilk marinade, allowing any excess to drip off, then dredge them in the flour, shaking off any excess. Dip them in the beaten eggs, and finally dredge them in the panko breadcrumb mixture. Make sure to thoroughly coat the chicken at each stage. Set aside for 10-15 minutes to rest.
Heat at least 1/2" of oil in a large skillet over high heat. It should be between 325 and 350°F to cook the chicken. Once the oil is hot, carefully place the chicken in the pan, being careful not to crowd the pan. You may need to cook the chicken in batches. Cook each chicken breast for 3-4 minutes on each sides until golden brown and crispy and the internal temperature has reached 165°F when tested with a digital meat thermometer. Remove to wire rack set over a baking sheet to drain excess oil.
Peanut or vegetable oil for frying