Step 1: Flatten each chicken breast under plastic wrap using a meat mallet to about ½-inch thickness. Pat dry with paper towels.
Step 2: In a bowl, whisk together buttermilk, eggs, and salt. Add the flattened chicken breasts and soak for at least 1 hour or up to 12 hours (refrigerated). Let it sit at room temperature for 30 minutes before cooking.
Step 3: In a separate shallow bowl, combine the all-purpose flour, breadcrumbs, seasoned salt, paprika, cayenne pepper, and black pepper. Whisk well to combine.
Step 4: One by one, remove a chicken breast from the buttermilk marinade, allowing any excess to drip off. Dredge the chicken thoroughly in the seasoned flour mixture, pressing firmly to ensure the coating adheres to every crevice.
Step 5: Heat 1 ½ cups of vegetable oil in a large cast iron skillet over medium-high heat until it reaches 350°F (175°C). Use a cooking thermometer to monitor the temperature.
Step 6: Carefully place 1-2 breaded chicken breasts into the hot oil, ensuring not to overcrowd the skillet. Cook for 4-5 minutes per side, or until golden brown and cooked through (internal temperature of 165°F/74°C).
Step 7: Once cooked, transfer each piece of chicken to a wire rack set over a baking sheet to drain excess oil and maintain crispiness. Repeat with remaining chicken.
Step 8: Allow the cooked chicken to rest on the wire rack for 5-10 minutes before serving. This allows the juices to redistribute for maximum tenderness.