Fire up the grill this fall and put a different spin on the traditional steak.
Combine all ingredients except flank steak and mayo in a blender or food processor and process until desired consistency.
Use about 1/2 the chimichurri mixture to marinate the flank steak for four hours.
Grill over hardwood lump charcoal until desired doneness.
Let rest for at least five minutes.
In the meantime, mix mayo and chimichurri mixture together until you have a nice consistency dipping sauce. Taste for seasoning.
Slice steak across the grain of the meat, and serve on nice toasted bread or in a taco shell. Top with some of your favorite things and the dipping sauce.