AU JUS: To get started, heat olive oil in skillet and caramelize the onions. Add garlic and cook for another minute. Add white wine to deglaze the pan (that's the best part!) Add worcestershire and cook for another minute; stir constantly. Add beef broth and bring to just a boil; reduce heat and simmer for about 30 minutes more.
Strain broth mixture to remove solid, then return it to the pot. Add flour and simmer an additional 5 minutes; stirring occasionally. Set aside.
FRENCH DIP CRESCENT ROLL: Unroll the prepared crescent dough onto cookie sheet(s).
Spread a small amount of horseradish on each crescent - adjusting to your taste. Add a slice of roast beef and cheese onto each crescent.
Roll 'em up! Begin at the wide end and work your way to the narrow end.
Bake at 375 degrees for 11 to 13 minutes, or until golden brown.