Reduce the flame. Pour in about 8 oz of red wine into the pan. Throw in the chopped shallots. Reduce the liquid in the pan - somewhat - but not to a glaze. Pour whatever juices have exuded from under the steak back into the pan. Turn the flame down to low. Whisk in cold butter, a knob at a time, until the sauce congeals. Do not, at any time, allow this sauce to boil. It will break. Strain off shallots - if desired.
Place the steak on a platter. Ladle the sauce over it. Serve with fries.
Reduce the flame. Pour in 6 oz of white wine into the pan. Scrape the bottom of the pan. Reduce the liquid in the pan - somewhat - but not to a glaze. Pour whatever juices have exuded from under the steak back into the pan. Turn the flame down to low. Whisk in the cold butter, a knob at a time, until the sauce barely congeals. Do not, at any time, allow this sauce to boil. It will break.
Place the steak on a platter. Ladle the sauce over it. Serve with fries.