Combine chicken with the buttermilk, hot sauce, salt and white pepper. Cover and place in the fridge for as long as you have time for. Preferably overnight, absolute minimum 2 hours.
Meanwhile, in a shallow dish or curved tray combine flour, cayenne pepper, baking powder, paprika, onion & garlic powder and salt. One by one, coat your chicken strips in the dry mix, making sure you cover every spec of chicken. Press the mix right into the chicken so it goes nice and flaky. Place on a wire wrack and repeat.
Heat up your oil to around 350F/175C. To test without a thermometer, drop a tiny piece of batter in the oil, if it very slowly rises to the top, you should be good to go. A medium heat for around 8-10 minutes should obtain this. The temp will slightly drop when the chicken hits, which is fine, just maintain that heat (no lower than 320F/160C).
Working in batches of 3-4, carefully place your strips into the oil. Separate them with tongs if the instantly stick together, then leaves for 3-4mins until they start turning golden. Flip over and leave for another few minutes until deep golden and visibly crispy. If your oil is too hot simply pour in more oil/turn down heat. If you're not confident with deep frying then test one strip first.
Place on a wire rack with a tray or paper towel underneath. Enjoy with a dip or as a side!