Step 1

One to one and a half hours before cooking, open the roasts up, and trim any excess fat from them.  Put them in a gallon ziploc bag (or two, if they’re large).  Whisk the ingredients for the brinerade together until well mixed, then reserve 1/4 cup for later and pour the rest into the bag with the lamb.  Squeeze out any excess air, then zip the bag closed, and massage it to get both roasts covered with the brinerade.  Let rest in the refrigerator, turning occasionally to evenly brinerate, until ready to cook. (Due to the acid in the lemon juice, you don’t want to brinerate more than an hour and a half.)

Step 2

Prepare your rotisserie for cooking on indirect high heat. For my Weber kettle, I light a chimney starter* full of charcoal, wait for it to be covered with ash, then pour it in two equal piles on the sides of the grill. Put the drip pan on the charcoal grate between the piles.

Step 3

While the grill is heating, take the lamb out of the refrigerator, pat dry with paper towels, and roll the two roasts into cylinder shapes. Truss the roasts every 1 1/2 inches with the butcher’s twine, then skewer them on the rotisserie spit.

Step 4

Put the spit on the grill, start the rotisserie spinning, and close the lid, cooking with the lid closed as much as possible. Cook with the lid closed, until the lamb is 135*F in the thickest part for medium, about 45 minutes. (Cook to 125*F for medium-rare, and 120*F for rare. (Unlike beef, I prefer my lamb cooked to medium). Start checking the lamb’s temperature at 30 minutes, and watch out for the bone and the spit – they can throw the reading off. Right before taking the lamb off of the grill, baste it with the reserved brinerade. Remove the spit from the rotisserie, remove the lamb roasts from the spit onto a platter. Baste them with the brinerade again, then remove the trussing twine and let the roasts rest for 15 minutes. Slice the lamb 1/2″ thick and serve.