- In medium non-reactive bowl, whisk together parsley, oil, vinegar, garlic paste, mustard, Worcestershire sauce, salt and lemon juice.
- Place steak in 9-in. (23 cm) square baking dish. Pour marinade onto steak and massage to coat; flip and repeat on other side. Cover with plastic wrap and refrigerate for 1 to 8 hours.
- Preheat grill to medium-high. Remove steak from marinade and wipe off excess with paper towels. Place steak on greased grill; close lid and grill for 2 to 3 min. per side, or until instant-read thermometer inserted 1 in. (5 cm) through side reads 155°F (71°C) for medium. Let rest 5 to 10 min. before slicing thinly.
Tip: The marinade can be prepared up to a week in advance and refrigerated in a tightly sealed container until needed.