FILET STEAK A LA MILANESE

4  filet mignons about 1" thick 2 T butter 1/2 t rosemary 1/4 t dry mustard 1/4 t Worcestershire 1 jigger (3 T) cognac or other brandy Melt 1 T butter with rosemary in heavy skillet.  Do not brown.  When skillet is hot, add meat and cook to taste (2-3 minutes per side for rare).  Check for doneness.  Remove to platter and keep warm.  Add remaining butter, mustard, Worcestershire and cognac.  Heat well, but do not boil.  Pour over meat and serve immediately.