To make the cilantro marinade: Place the roasted garlic, mustard, cilantro, lemon zest, balsamic vinegar, and oil in a large shallow glass or ceramic bowl and mash to a paste.
Place the steak in the marinade. Cover and refrigerate at least 8 hours or overnight, turning occasionally.
Prepare the grill or preheat the broiler.
Remove the steak from the marinade, reserving the marinade. Sprinkle both sides of the steak with the salt and pepper. Grill or broil for about 5 minutes per side for medium-rare, basting occasionally with the reserved marinade.
Thinly slice on the diagonal and serve. Serves 4 Typed in MMFormat by cjhartlin@msn.com ----