In a large bowl, mix together the shallots, garlic, rosemary, sugar, coriander, salt, and chile flakes. Rub the mixture on the surface of the lamb. Set the lamb in a large glass baking dish; cover with plastic wrap and refrigerate overnight.
Preheat the oven to 375 degrees F.
Rinse the lamb and pat it dry. Heat a roasting pan or large ovenproof skillet over medium heat. Brown the lamb on both sides.
Set the lamb on a roasting rack in the pan and roast, fat side up, until it reaches an internal temperature of 140 degrees F, about 1 1/2 hours. Transfer to a platter. Set the pan over medium heat and add the stock, scraping the pan drippings to dissolve them in the broth. Simmer until reduced by half.
Serve the lamb with the reduced pan sauce, Tzatziki Sauce, and grilled vegetables such as eggplant, zucchini, and yellow squash tossed with red wine vinegar and olive oil.
Stir together all the ingredients in a medium bowl until thoroughly combined.
This recipe was provided by professional chefs and has been scaled down from a bulk recipe provided by a restaurant. The Food Network Kitchens chefs have not tested this recipe, in the proportions indicated, and therefore, we cannot make any representation as to the results.