In a large resealable plastic bag, add all the ingredients except for the beef, shaking well to mix.
Add the flank steak, turning to coat with the marinade; refrigerate for at least 10 minutes, or preferably overnight.
When ready to cook, coat the grill rack with cooking spray, and prepare the grill to medium-high heat.
Snip the corner of the plastic bag with scissors and drain the marinade into a small saucepan; set aside.
Place the steak on the prepared grill and cook for 5 minutes on each side, or until desired doneness. Let stand 5 minutes before thinly slicing diagonally across the grain.
Bring the reserved marinade to a boil over medium-high heat; reduce heat to low and simmer for 5 minutes.
Serve with the steak.