Process the mixture until fairly smooth. add salt and pepper to taste. Reserve 1/2 for serving.
Place the marinade and steak in a ziplock bag and refrigerate for at least 1 hour or up to 8 hours.
Prepare a medium-hot fire in a grill.
Remove the meat from the marinade and pat it dry. Grill it uncovered, directly over the heat, 3 to 4 minutes per side for medium-rare. Turn the steak only once (so that the meat gets a better crust), using tongs. Let the steak rest for 5 minutes, then slice it 1/4 inch thick.
Serve with sauce and grilled vegetables.