Marinate 4 thin raw chicken breasts in a Ziploc bag in buttermilk for 30-60 minutes.
Create breading process with 3 separate shallow dishes or bowls. In the first dish, mix flour, half of the salt, garlic powder, and half of the pepper.
In the second dish, mix egg and water.
In the third dish, mix Panko, remaining salt, and remaining pepper.
Coat chicken in flour mixture (first dish), dredge (completely coate) in egg mixture (second dish) then coat in panko (third dish).
Heat a cast iron skillet (or another heavy-bottomed pan) over medium high heat, melt butter and olive oil.
Place 2 chicken breasts in the pan and brown (about three minutes on each side).
Continue cooking until chicken is cooked all the way through. Repeat with the last two chicken breasts. Place on paper towel lined plate to drain excess oil.