Mustard Marinade for Steak

1. In a large, non-metallic shallow bowl, combine 1 tbsp white wine vinegar, 2 tbsp olive oil, 3 tbsp dijon mustard, 2 tbsp freshly chopped parsley, salt and pepper.
2. Add 4 steaks and coat on both sides.
3. Cover and marinade in the fridge for 1-2 hours.
4. Brush the excess marinade mixture from the steaks and cook on a pre-heated moderate grill for 2 1/2 minutes on each side for rare, 4 mins, on each side for medium and 6 mins on each side for well done.