Cup of Yum
1. Remove the string or netting from the leg of lamb and open it on a cutting board. Butterfly the lamb so that it lays flat in a mostly even layer. To do this, start at the thinner side of the lamb and look at it straight on, so you can see the thicker and thinner parts and how much butterflying needs to be done. Make shallow, horizontal slices into the thicker part of the meat (look for where the thin part starts to increase in thickness), about 3/4" deep, folding the meat open as you make those cuts. Continue in this manner until you've laid the lamb leg open into a fairly even layer.
2. If you have a larger flap that hangs off of the roast, independent from the rest, you can leave it attached, or slice it off to wrap and freeze for stews or kebabs later on. I removed the extra flap, just to make the unrolled lamb leg a long, even piece that would roll up more evenly.
3. Turn the butterflied lamb over so the fat side faces up. Trim the lamb of excess fat, silver skin and sinew. There should be some fat, but not too much. Follow the video to see how I did it.Cover and set aside.

MAKE THE STUFFING:

1. Preheat the oven to 350°. Spread the walnuts on a baking sheet and toast for 10 minutes or until browned and fragrant. Transfer to a mini food processor and pulse to chop the nuts finely. Transfer the nuts to a medium bowl.
2. Roughly chop the garlic, mint and parsley and transfer to the food processor to chop more finely. Add the herb mixture to the walnuts. Add the lemon zest.
3. If the feta is in large chunks, break it up and pulse a few times in the food processor. If the feta is already finely crumbled, add directly to the walnut and herb mixture. Toss to combine.

FOR FRESH SPINACH:

1. If using fresh spinach, bring a medium pot of water to a boil and fill a medium sized bowl with ice and water.
2. Add the fresh spinach to the boiling water and cook for 30 seconds, just until the spinach wilts, but is still bright green. Quickly transfer the spinach to the ice bath to stop the cooking.
3. Transfer the spinach to a fine mesh colander to drain. Once drained, place the spinach in a clean dishtowel and ring it with your hands to squeeze out any excess moisture over the sink. Transfer the spinach to a cutting board and chop it. Transfer the spinach to the stuffing mixture.

FOR FROZEN SPINACH:

1. Thaw the spinach completely. Transfer the spinach to a clean dish towel and fold it up into a cylinder. Ring the excess liquid out, squeezing firmly with your hands and twisting the ends of the towel over the sink until the spinach is very dry. Transfer to the walnut feta mixture and stir well to mix the stuffing evenly.

FOR THE LAMB:

1. Season the butterflied leg of lamb on both sides with the kosher salt and pepper. Rest the lamb, fat side down on a large work surface or cutting board. Spread the stuffing evenly along the length of the leg of lamb.
2. Roll the meat up into a spiral. Don't roll too tightly or too gently. Too tight and the stuffing will ooze out, too loose and it won't hold it in.
3. Use 5-7 pieces of kitchen twine (cut to about 20" lengths) to tie the roast together every 1 to 2 inches or so. Tie twine around the roast both horizontally and vertically to ensure that it holds together. Trim the excess pieces of string from the roast.

PREPARE THE ROTISSERIE:

1. Assemble the rotisserie according to the manufacturer's instructions on your grill. Heat the grill to 400° using an indirect cooking method. (For us that meant lighting the burners on the far right and far left side, with the center burner turned off.)
2. Lay a drip pan under where the roast will go to catch any juices or filling that may come out.
3. Afix the tied, stuffed leg of lamb to the rotisserie and begin cooking. Check on it about 30 minutes into cooking to verify the integrity on the spit.
4. Depending on the size of your leg of lamb will determine how long it needs to cook. For medium rare lamb the optimum temperature is 125°F or 51°C, however the lamb will continue cooking after you remove it from the spit. I recommend removing it when a good instant read digital thermometer reaches about 5-7° less than the optimal temperature.

CARVING AND SERVING THE LEG OF LAMB:

1. Remove the lamb from the spit and let it rest on a cutting board for 15 to 20 minutes before carving, so the juices can redistribute.
2. Use a sharp carving knife to cut the lamb into 1/2" thick slices. Arrange on a platter and serve.

TO ROAST IN THE OVEN:

1. Not everyone has a gas grill or rotisserie, but that's ok. You can roast your butterflied, stuffed lamb in the oven. Here's how:
2. Preheat the oven to 425° F. Place the tied roast onto a roasting pan with 2" sides.
3. Slice a medium onion and transfer to the roasting pan. Add 2 teaspoons of olive oil and toss the onions to coat. Spread the onion out in an even layer on the bottom of a roasting pan. Rest the tied lamb roast on top of the onions and roast for 45 minutes to an hour, depending on how large your roast is.
4. Check the internal temperature of the roast to gauge where it is in the cooking process. When it reaches about 5-7 degrees below your desired doneness, remove the roast from the oven and transfer to a cutting board to rest for 15 minutes.
5. Bonus: You can make an au jus with the onions and pan drippings. Just place the pan over a burner on the stove. Sprinkle about 1 to 1 1/2 teaspoons of red wine vinegar over the onions. Heat the stove to medium high heat and stir the onions with a wooden spoon. Add low sodium beef broth (about 1 to 1 1/2 cups), stirring constantly and bring to a boil. Reduce the heat and let it simmer for about 3-4 minutes. Stir in 2 tablespoons of butter, whisking until it melts. Season to taste with salt and pepper and serve on the side of the lamb roast.