Whisk together first 8 ingredients in bowl to make basting sauce
Place flank steaks in shallow pan (flank steaks are best if they are tenderized first). I use a Ziploc bag!
Pour sauce over steaks - cover well.
Remove steaks from basting sauce and sear over HOT grill for about 3-5 minutes per side.
Baste with additional sauce as desired. (I boil the leftover sauce for 1 minute, then pour over cooked flank steaks).
When the steak has cooked to the preferred level of doneness, remove from the grill and place on a cutting board. Cover with aluminum foil to hold in the heat while the steak rests for 10 to 15 minutes.
Note: cut the steak across the grain of the meat, at a steep diagonal, so that the slices are wide.