Despite the awkward name, this fast and user-friendly wet rub did a fine job flavoring some carne asada I grilled recently (yes, that was redundant). I'm calling it Spanish mustard since I spiked the Dijon with a couple of my favorite ingredients of all time: smoked paprika and sherry vinegar. You can use any thin flap meat (flap steak, skirt steak, round steak) instead of the flank steak.
