slow-grilled rack of lamb with caramelized onion jam

I like to buy my racks of lamb already "Frenched", that is - trimmed up and the bone ends scraped, from either Trader Joe's or Costco.  I made the onion jam while the meat cooked.  Another winner from the Nov. 2011 issue of Food and Wine magazine (that one was a treasure trove of tasty delights).
http://www.foodandwine.com/recipes/slow-grilled-rack-of-lamb-with-mustard-and-herbs