Stir together all the ingredients for the marinade. If you'd like, score the top of the steak so the marinade seeps in..about 1 inch cuts apart. I didn't do that, but, as Martha would say "It's a good thing". Place the flank steak in a ziplock bag or bowl, and pour the marinade over it. Seal or cover and refrigerate for up to 12 hours, no less than 2 hours.