1 bunch flat leaf Italian parsley, rinsed, drained and chopped
½ cup fresh cilantro, rinsed and drained
½ tablespoon dried oregano
6 cloves garlic, peeled
¾ cup olive oil
1 teaspoon each salt and pepper
½ teaspoon cayenne pepper
¼ cup white wine vinegar
Rub both sides of the flank steak with the oil and season with the coriander, cumin, salt and pepper. Place on medium-high heat and grill for 3 minutes per side. Lower the heat on the grill to medium-low and continue to cook; turning often until internal temperature has reached 130 degrees F for medium rare. Place on carving board and let rest for 10 minutes before slicing thin; on the bias.
Place all of the chimichurri ingredients, except for the vinegar into a food processor. Process until finely chopped; but not liquefied. Add the vinegar and process for 3 seconds to incorporate. Serve on the side as sauce for the sliced steak.
Note: The chimichurri can be made a day ahead but do not add the vinegar until just before serving.