Pound Chicken: Lay a chicken breast on your chopping board and cover with cling film (pinch around edges so no moisture escapes). Pound until even thickness, but not so thin it starts breaking apart. Around 1/2" is fine. You can cut any stray pieces to create more of a circular shape if you wish. Repeat.
Marinate: Combine buttermilk, buffalo sauce, salt and white pepper in a large mixing bowl. Add in the chicken breasts and use your tongs to fully coat. Tightly cover with cling film and place in the fridge to marinate. I 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.
Dredge: In a large shallow dish or curved tray combine flour, paprika, cayenne pepper, onion & garlic powder, baking powder and salt & black pepper. One by one use your hands dredge the breasts through the flour, making sure you completely coat each time. Really get in all the cracks and crevices of the chicken to create lots of little flaky parts. Place to one side and repeat.
Fry: In a large pot or deep pan heat up oil to 180C/356F. In batches of 1-2 (depending on pot size), carefully lower the chicken in the hot oil. The temp will likely drop to around 165C/300F, just maintain that heat as best you can as the chicken fries (a medium flame should suffice). Depending on the thickness of the chicken it'll take around 4mins each side. The chicken should be deep golden and visibly crunchy. You want the internal temp of the chicken to reach 75C/165F. Carefully remove and rest on wire rack with paper towels or tray underneath (don't place directly on paper towel or they'll lose crispiness). Bring oil temp back up to 180C/356F and repeat.
Glaze: After frying the chicken, allow the oil to cool slightly then scoop out 1/2cup of the oil and pour into a small mixing bowl. Add in buffalo sauce, honey and smoked paprika. Whisk until it emulsifies and thickens into a glaze. Brush both sides of the chicken with the glaze.
Sandwich: Stack the sandwich in the following order - toasted bun, blue cheese sauce, lettuce, tomato, onion, fried chicken, bacon, more blue cheese sauce, top bun. Enjoy!