For the Fried Chicken:

1. Marinate chicken: In a bowl, marinate chicken in buttermilk for at least 30 minutes, or overnight for more flavor.
2. Prepare breading: In a shallow dish, combine flour, garlic powder, onion powder, paprika, cayenne (if using), salt, and pepper.
3. Coat chicken: Remove chicken from buttermilk and dredge each piece in the flour mixture, pressing down to ensure it’s fully coated.
4. Fry chicken: Heat about 1 inch of vegetable oil in a large skillet over medium heat. Fry chicken in batches, cooking each piece for 4-5 minutes per side, or until golden brown and crispy. The internal temperature should reach 165°F (74°C). Drain on paper towels and set aside.

For the Mashed Potatoes:

1. Boil potatoes: In a large pot, bring salted water to a boil and cook potatoes until tender, about 15-20 minutes. Drain and return to the pot.
2. Mash potatoes: Add butter, milk, and sour cream (if using) to the potatoes. Mash until smooth and creamy. Season with salt and pepper to taste.

To Serve

Plate the crispy fried chicken on top of a generous scoop of creamy mashed potatoes. Garnish with a sprinkle of fresh parsley or chives and serve with gravy or your favorite dipping sauce.