When Dad is doing the grilling, bring out the steak. Marinate in chimichurri to give the steak bright herbal flavor.
Mix Seasoning Mix, oil, water and vinegar in small bowl until well blended. Reserve 1/4 cup marinade for brushing. Place steak in large resealable plastic bag or glass dish. Add remaining marinade; turn to coat.
Refrigerate 30 minutes or longer for extra flavor. Remove steak from marinade. Discard any remaining marinade.
Grill steak over medium-high heat 6 to 8 minutes per side or until desired doneness, brushing occasionally with reserved marinade.