2 (2 1/2 lbs.) beef round top round steak (no bone), 1 1/2 inches thick, cooked and cooled
4 tbsp. dijon-style mustard, divided
2 tbsp. plus 1 tsp. tarragon
1 c. dry white wine
1/2 c. tarragon vinegar
3 shallots, chopped

Mix together and serve with beef.