Have the butcher butterfly the leg of lamb, or do it yourself. Combine all remaining ingredients in a glass, enamel, stainless, or plastic container and beat with a whisk or fork until combined. It takes a few minutes.

Add the lamb, turning it to make sure it is coated on all sides. Marinate two hours at room temperature, or overnight in the refrigerator. Check occasionally to make sure that it is still coated with the marinade and re-cover as necessary.

Grill outside, or broil inside at about 8 inches from the flame for 15 minutes on each side, brushing occasionally with the marinade. Serve sliced thin (hot) with the rest of the marinade, heated.