Tenderize the meat by pounding with a wood kitchen mallet. Heat the oil in a skillet. Dredge the breasts in flour and season with salt and pepper. Brown the breasts in the skillet and then remove to a warm plate. Add the wine and simmer for about a minute. Add butter and retain any juices and bits left from the chicken. Simmer until the sauce thickens, reduce heat to low, and return chicken breasts to skillet. Turn them a few times to fully coat with sauce. Optional: Add chopped fresh or canned mushrooms to the sauce at the same time the butter is added.