Lay chicken breasts on a flat surface and cover with a sheet of cling film (pinch around the edges so no juices escape). Pound with a rolling pin or mallet until even thickness, but not so much they start to tear apart. You're looking for around 3/4" thickness. If the breasts are particularly long you can cut off the very end of the tail to make them more circular and burger shaped (keep in mind they will also shrink slightly when frying).
In a large bowl, combine 1.25cups/300ml buttermilk with 1 tsp paprika & salt and 1/2 tsp onion powder, garlic powder, cayenne pepper and white pepper. Place in your chicken breasts, use tongs to fully coat then tightly cover with cling film and marinate in the fridge. I highly recommend a minimum of 4 hours (up to overnight), but just as long as you have time for. Take the chicken out the fridge 30mins before needed to bring close to room temp (see notes).
In a large shallow bowl (or curved tray) combine 1.75cups/250g flour with 2 tsp paprika, 1 tsp oregano, baking powder & salt, 1/2 tsp onion powder, garlic powder & cayenne pepper and 1/4 tsp black pepper. One by one coat the breasts in the flour, making sure you completely coat each time. Really get in all the cracks and crevices of the chicken. Place to one side.
In a large pot or deep pan heat up your oil to 180C/356F. In batches of 1-2 (depending on pot size), carefully place your chicken in the hot oil. The temp will likely drop, and that's fine, but make sure the temp stays at around 165C/300F as the chicken fries. Depending on the size and thickness of your breasts you're looking at around 4-5mins on one side, then flip and continue frying until golden. The internal temp of the chicken should reach 75C/165F. Carefully remove and rest on wire rack with paper towels underneath (don't place directly on paper towel or they'll lose crispiness). Bring oil temp back up to 180C/356F between each batch.
Stack burgers in the following order: bottom bun, coleslaw, chicken, bacon, honey sriracha, top bun. Enjoy!