Because being hammered, the breast should be ready in about 7 minutes - double check and cook longer if necessary. Off heat, cover, and let stand for another minute. Slightly cool (remove the excessive fats with paper if desired) and slice as desired.
Slightly hammer the chicken breast (s). Season them with the thyme, salt and pepper. In a frying pan melt the butter over medium heat until it's foaming. Place the chicken in the center of the pan. Don't move the pan and slightly press the breast with a spatula, for one minute. Now you should carefully spoon out the foaming butter and pour it over the top of the breast. Keep on doing this regularly (every 10-15 seconds) which prevents your chicken breast from drying out and helps to cook through since we cook it only on one side.