Place the cilantro, parsley, lime juice, red wine vinegar, brown sugar, onion powder, salt, paprika, cumin, and pepper into a food processor or powerful blender.
Rough chop the garlic and toss that in.
Start pulsing the mixture and drizzle in the olive oil until it is a thick paste.
Cover the steak in the marinade, cover it with plastic wrap, and place it in the fridge for at least 4 hours or, at best, overnight. Turn it about halfway through the marinating process if you can.
Allow the steak to sit out for 30-60 minutes at room temperature before grilling.
Prepare and preheat your grill over medium-high heat.
Cook until an internal temperature reaches 135°F in the thickest part for medium-rare, about 3-5 minutes per side, or cook to your desired temperature.
Allow to rest for 10 minutes before slicing against the grain in thin strips to serve.
