Sauteed Beef Tenderloin in Mushroom Pan Sauce

Heat 1 tablespoon oil in heavy medium skillet over medium-high heat (a cast iron skillet works best).  Sprinkle steaks with salt and pepper.  Add steaks to skillet once oil is fully heated; cook to desired doneness (about 4 minutes per side for medium rare).  Transfer steak to plate (do not clean skillet) and cover with foil to keep warm.Return skillet to heat and deglaze the pan with 1/4 cup of the red wine.  As the wine reduces, scrape up the brown bits with a wooden spoon.When the wine has evaporated, add 2 tablespoons of butter to the skillet.  Saute the shallot and mushrooms until softened.  Add the remaining wine and stock to the skillet, bring to a boil and reduce to a simmer until the liquid has been reduced in half.To serve:  spoon sauce over top of the steak and sprinkle with parsley.