Add salt, pepper cayenne pepper, and paprika to buttermilk (add hot sauce if you want extra spice). and whisk to combine. Put chicken in a zip-top bag or bowl with a lid. Pour buttermilk marinade over the chicken and store in the fridge for at least an hour or overnight.
Make seasoned flour by combining flour with all of the spices, salt, and pepper in a bowl or pan that is large enough for a piece of chicken to lay flat in the flour.
Remove one piece of chicken at a time from the marinade and dredge in the seasoned flour mixture until thoroughly coated on all sides. Place the fully coated chicken onto a piece of parchment or a sheet pan rack to rest.
Heat 2 inches of peanut oil in a skillet to 350 degrees F (175 degrees C).
Fry each piece of chicken for 6 to 7 minutes or until it reaches 165 degrees internal temperature. You'll probably want to fry for 3 minutes on the first side and then flip it to make sure you're getting the level of browning that you want. Continue cooking on the other side.
After frying, place the finished chicken on a cooling rack over paper towels to drain some of the oil away.
Add to a biscuit or bun with your favorite sauce and enjoy.
Notes:
A boneless skinless fried chicken thigh is usually a really good size for a biscuit or sandwich on a small bun. Typically a breast could be too large for your bun, so you may want to butterfly it or cut it into a shape that will more closely fit your bun or bread choice.