Elise's Grilled Butterflied Leg of Lamb

Step 1: Put onion, garlic, rosemary, lemon zest, apple cider vinegar, and olive oil into a food processor and pulse to combine. (If you don't have a food processor, just chop the onions, garlic, and rosemary very well and combine with the rest.).

Step 2: Sprinkle a generous amount of salt and pepper over the lamb.

Step 3: Place marinade and lamb into a 1 gallon freezer bag. Spread marinade over all sides of the meat.

Step 4: Seal the bag and refrigerate for 1-2 hours.

Step 5: Remove lamb from refrigerator, and let come to room temperature (about 20 minutes).

Step 6: When ready to put on grill, remove from marinade bag. To help make the lamb easier to turn on the grill you can insert a couple of skewers through the lamb, crosswise.

Step 7: Prepare grill:

Step 8: If you are using a charcoal grill, prepare the coals so that they are double layered on one side of the grill, and sparsely single layered on the other side of the grill (this is called "banked" grilling).

Step 9: If you are using a gas grill, heat the grill on high on all burners to start. After the initial browning you will reduce the heat.

Step 10: Place the lamb, fat side down, on the grill on the hot side (double layer charcoals). You will likely get flareups, so be prepared with a squirt bottle of water or a couple of cups of water (if using a charcoal grill) to control the flames if needed.

Step 11: Sear one side for 4 minutes, then flip the lamb over to sear the other side for another 4 minutes.

Step 12: If you are using a charcoal grill, move the roast to the less hot side of the grill.

Step 13: If you are using a gas grill, lower the heat to low. You will want to maintain a temperature of 300-350°F

Step 14: Cover the grill and let cook for an additional 35-45 minutes (depending on how thick, and how many pounds the roast is), until a meat thermometer inserted into the thickest part of the roast registers 130°F (for medium rare).

Step 15: Transfer to a cutting board with a well to catch the juices. Cover with aluminum foil and let rest for 5-10 minutes.

Step 16: Remove the skewers if you are using any.

Step 17: Cut across the grain, 1/4-1/2 inch thick slices.

Step 18: Serve slices on a warm platter; pour meat juices over the slices.

Step 19: Serve with mint jelly or horseradish.