Procedure:

Wash and spin-dry the parsley, tarragon, and oregano, then place them in a high-powered blender.

Wash, dry, and pick the thyme leaves, then add to the blender.

Cut the chives into batons and add them to the blender with the remaining ingredients.

Blend at high speed until smooth, then immediately transfer to a shallow pan to cool.

Rub the marinade all over the steak, then place it in a bowl and marinate overnight, but no longer than 24 hours. Vinegar will help denature proteins, which loosen muscle fibers and tenderizes the meat.

Before grilling, remove the steak, wipe it clean, and pat dry. Season immediately with salt and pepper, then grill to the desired temperature.