In a large bowl, combine the buttermilk with 1 teaspoon of salt, mixing well. Add the chicken thighs or breasts, ensuring they are fully submerged. Cover and let marinate in the refrigerator for at least 1 hour, or overnight if time allows.

In another bowl, whisk together the flour, garlic powder, onion powder, paprika, the remaining salt, and black pepper to prepare the coating.

In a deep frying pan, pour enough vegetable oil to cover the bottom by about an inch. Heat the oil over medium-high heat until it reaches 350°F (175°C).

Remove the chicken from the buttermilk marinade, allowing any excess to drip off. Dredge each piece in the flour coating, pressing gently to ensure it adheres well.

Carefully place the coated chicken pieces into the hot oil, frying in batches if necessary. Cook for about 5-7 minutes per side, or until golden brown and cooked through (internal temperature should reach 165°F/75°C).

Once cooked, transfer the chicken to a plate lined with paper towels to drain excess oil.

Toast the burger buns lightly. Layer with crispy lettuce, a slice of tomato, pickles, and a generous spread of mayonnaise. Place the fried chicken on top and serve immediately.