Soak the chicken: Place chicken in a large bowl or zip-top bag. Add buttermilk, 2 tablespoons salt, and 1 teaspoon pepper. Toss to coat, cover, and refrigerate at least 8 hours or overnight.
Preheat: Heat oven to 350°F. Set a wire rack over a baking sheet.
Mix the coating: In a shallow dish, whisk together flour, 1 tablespoon salt, 1 tablespoon pepper, and paprika.
Dredge: Lift each piece from the buttermilk, let excess drip off, and press into the seasoned flour until fully coated. Place on the wire rack and rest 10 minutes.
Fry: Heat 1 inch of oil in a large heavy skillet to 350°F. Fry chicken in batches, 3 to 4 minutes per side, until golden brown. Return to the wire rack.
Bake: Transfer the rack and baking sheet to the oven and bake 30 to 40 minutes, until the internal temperature reaches 165°F.
Rest and serve: Let rest 5 minutes, sprinkle with flaky salt if desired, and serve.