Chop onion. Cut carrots on diagonal into 1/4 inch slices. Melt the butter in a large frying pan. Brown the chicken on both sides over medium heat, about 15 minutes in all. Remove from the pan. Add the onion and carrots and cook, covered, until soft, about 15 minutes. Return the chicken to the pan. Add the vinegar, salt and pepper. Cover and cook until the juices run clear when the chicken is pierced with a fork. (20 to 25 minutes.) If Balsamic Vinegar is not found, substitute half vinegar and half water and add a pinch of sugar.
Serves 4.
