Well worth every hour of waiting for this to slow cook on the grill (or oven). You'll have plenty of time to enjoy your favorite appetizers and cocktails while basting and keeping the coals going.
An absolutely divine recipe for Lamb!
Whisk together the first 5 ingredients and pour into a large resealable plastic bag. Add the leg of lamb coating with the marinade well. Squeeze out extra air and seal the bag. Marinade at room temperature for 2 hours.
Stir together the remaining ingredients in a saucepan and bring to a boil over medium high heat, reduce to medium low and simmer for 30 minutes until the onions have softened and the sauce has thickened.
Preheat outdoor grill to medium low heat. (I prefer the indirect cooking method on my kettle style grill for this).
Lightly oil the grate.
Remove lamb from marinade (discard the excess marinade) and place on the preheated grill. Baste with the barbecue sauce and grill the lamb for 1 1/2 to 2 hours until it reaches desired temperature. Turn and baste the lamb frequently with the hot barbecue sauce.