Heat the oil on high heat to the desired temperature, usually around 350F (175C).
Pick 1 piece and dredge the marinated chicken from buttermilk mixture in the flour mixture. Then dip that piece again back in the butter milk. Finally, dredge again in the flour.
Carefully add dredged chicken breast in the hot oil. Then immediately turn down the heat just a little bit (ideally on medium high heat or between medium high and high heat). By doing so the oil is still hot enough to cook chicken breast but won’t burning its surface.
Deep fry the chicken breast until done, approximately 7-10 minutes. Two minutes before taking the chicken out, turn up the heat back to high. The fried chicken breast should have a crispy and golden brown outer layer.
Remove the deep-fried chicken breast from the oil and hold it over the pan, allowing the excess fat to drain.
Transfer the chicken to a pan or a plate lined with absorbent paper. Season with a pinch of salt and pepper.