This, to me, is the essence of French home cooking: a simple sauté and flavorful pan sauce made with vinegar, mustard, and tarragon (the quintessential French herb). If you can’t find fresh tarragon, you can use tarragon vinegar instead and finish the dish with chives, but it’s just better with fresh tarragon.  For the best results be sure to use a flavorful chicken stock. If yours tastes a little weak, start with two cups instead of one and let it reduce longer to concentrate the flavor.

Season the chicken breasts with salt and pepper. Heat the oil over medium-high in a large skillet and when almost smoking add chicken breasts, skin-side down. Lower heat to medium and cook chicken for about 6-7 minutes, then flip (they should have an even, golden brown color) and continue cooking on the other side for about 5 more minutes.

Rotate the skillet if the heat on your burner is uneven, so that you don’t get any dark or burned spots, and reduce the heat if the chicken seems to be browning too quickly. When chicken is cooked, remove to a platter and cover to keep warm.

Pour the excess grease from the pan and deglaze with stock and vinegar, whisking to scrape up the browned bits on the bottom of the pan. Let the liquid bubble briskly in the pan, whisking, until it’s reduced to about 1/2 cup, then whisk in the butter, mustard, and tarragon.

The sauce should have a lightly creamy consistency. If it’s too acidic, whisk in a little more butter or stock. Remove from heat and spoon over warm chicken breasts, and sprinkle with chives, if desired