Whisk together buttermilk, paprika, garlic powder, and cayenne pepper in a bowl. Add chicken and refrigerate for at least 2 hours.
In another bowl, mix flour, onion powder, thyme, oregano, salt, and black pepper until well combined.
Remove chicken from marinade, letting excess drip off, and roll in flour mixture to coat thoroughly.
Heat vegetable oil in a frying pan to 350°F (175°C). Maintain temperature with a thermometer.
Place chicken in hot oil, frying in batches for 12-15 minutes or until golden and cooked through.
Transfer fried chicken to a wire rack to drain and cool slightly before serving.
Notes
For optimal freshness, consume fried chicken within 3 days when stored in the refrigerator. For best reheating results, use an oven set to 375°F to return crispness.