Sprinkle chicken breasts with salt and pepper. Dredge in the flour. Tap off excess.

Heat the oil in a skillet until hot but not smoking. Add 1 tablespoon of the butter and saute the chicken breasts for about 3 minutes on each side. They will be golden brown.

Put the chicken breasts on a plate and set aside.

Heat 1 tablespoon of butter in the pan and add the sliced mushrooms.

Cook the mushrooms until they have given up their liquid and are beginning to brown around the edges. Add the capers if you're using them.

Add the Marsala wine and cook until the wine is reduced by half, scraping up the brown bits on the bottom of the pan. Add the chicken stock and cook about 3 minutes more. The sauce will thicken slightly.

Lower the heat to medium and add the chicken breasts back to the pan. Cook a few minutes more until the chicken is cooked through, about 5 minutes.

Swirl in the 2 remaining tablespoons of butter and sprinkle the chopped parsley on top. Serve with pasta, quinoa, rice or potatoes.