Evenly pound the chicken breasts out to an even thickness using the flat side of meat mallet. Or alternately butterfly and halve 12 oz chicken breasts (cut right through their thickness into 2 portions).
Preheat a large heavy bottom skillet over medium-high heat.
Season both sides of the chicken with salt and pepper.
Drizzle just enough olive oil into the preheated skillet (I’ve found 1 1/2 Tbsp works perfect for me).
Add chicken breasts in an even layer then let cook, undisturbed until golden brown on bottom, about 6 – 7 minutes.
I also like to cover the skillet with a splatter screen right after I add the chicken, it reduces the splattery oily mess.
Flip the chicken and cook one the second side until chicken registers 165 in center, about 5 – 7 minutes (I highly recommend using an instant read thermometer, overcooked chicken breasts will be dry and tough).
Then transfer to a plate, tent with foil and let rest a few minutes before serving so the juices can redistribute.