Cooking a boneless leg of lamb may sound intimidating, but it’s easier than you think. I’ll show you how to butterfly a boneless lamb leg and stuff it with a fresh spinach, walnut and feta filling. This rolled and tied butterflied leg of lamb is easy to cook on a gas grill with a rotisserie attachment. Serve this show stopping spring rotisserie lamb for Easter, Mother’s Day or any special gathering with family and friends.
Butterflied rotisserie leg of lamb
There’s something impressive about leg of lamb. When you serve one, it’s an occasion. Boneless butterflied leg of lamb presents as a large roast and slices easily, without having to fiddle with carving around the bone. This stuffed rotisserie leg of lamb is a perfect main course for special occasions like Easter or for an al fresco summertime dinner.
“Boneless” doesn’t mean “butterflied”.
A butterflied leg of lamb is boneless, but a lamb leg labeled “boneless” isn’t necessarily butterflied. Confused? Don’t be.
Butterflied lamb is a boneless cut that has been cut open to lay flat and even all the way across. See this guide on cuts of lamb from The Food Lab.
The thickness of the meat is roughly equal from one end to another.
The photo above shows what the boneless leg of lamb looks like when the netting is removed and it’s opened up.You can see that the right side is thick and chunky, while the left is somewhat thinner.
The picture below, is what a butterflied leg of lamb looks like. See the difference?
In any event, it’s plain that it’s not even, and while you could fill it with a stuffing and wrap it back up, it won’t have the same presentation or even cooking as a butterflied leg of lamb.
How to butterfly a boned leg of lamb
- Remove the netting and open up the leg, fat side down.
- Visually assess the roast. Look at how thick the thick parts are and how thin the thinnest parts are.
- Holding the knife horizontal at the point where the thinnest part slopes up to a thicker portion, make small horizontal slices to open up the leg.
- With the knife parallel to the cutting board, make deft cuts midway through the thickest sections without cutting through the meat.
- As you make the cuts, continue to open up and flatten out those sections.
This process may take 10 to 15 minutes.
The key is not to rush. Take your time and pay attention.
The most important part is to not cut holes through the meat. If there is a piece of lamb that’s held together mostly by sinew and removing it will leave a gap — then just leave it be.
Flip the lamb over and trim away most of the fat cap and sinew, again using a sharp knife to make horizontal cuts, removing the fat.
Note: A butterflied leg of lamb will not be an even rectangle of meat. There is a large flap to one side that will be apparent. You can leave it on OR remove it.
If you leave it, it’s just a matter of securing the flap to the roast with butchers twine. I choose to remove it to make a more uniform rolled, stuffed rotisserie lamb (freezing the excess for kebabs or stew later on).
Check out my video to see how I butterflied the lamb leg for the rotisserie.
For rotisserie lamb filling:
- Fresh Mint
- Fresh Parsley
- Toasted Walnuts
- Lemon Zest
- Feta Cheese
- Fresh or Frozen Spinach
This garlicky, herby spinach, feta and walnut filling is easy to make and adds such a punch of flavor to the butterflied rotisserie leg of lamb.
Walnuts or other nuts:
Toasted chopped walnuts give the filling a rubbly, satisfying crunch. If you don’t have walnuts, almonds, pistachios or pine nuts would also be good. (Note: if using pine nuts, watch them carefully in the oven, because they will brown/burn faster than walnuts).
You can use either fresh or frozen spinach in the filling.
For fresh spinach
If using fresh spinach, you’ll want to blanch and shock it first. (Frozen spinach has already been blanched and shocked).
- To do this, bring a medium pot of water to a boil and add the spinach.
- Cook until the spinach just wilts, then use a slotted spoon or kitchen spider to transfer the spinach leaves to a prepared ice bath (equal parts ice and water in a bowl) to stop the cooking and retain the bright color of the spinach.
- Drain the spinach, then place the spinach in a clean dish towel. Wrap it up and squeeze out the excess moisture.
- Give it a rough chop on the cutting board and it’s ready to use.
For frozen spinach
- Thaw the spinach completely.
- Place the spinach in a clean dish towel, wrap it up and squeeze out any excess moisture.
- If you’re using frozen chopped spinach, it’s ready to use. If you have whole leaf spinach, give it a rough chop on the cutting board before adding to the filling ingredients.
Assembling the filling
I like to use a mini food processor for assembling the filling. Give everything a rough chop before adding it to the machine and do it in stages.
- Chop the toasted walnuts first, and transfer to a bowl.
- Add the roughly chopped mint, parsley and garlic to the food processor and pulse several times until finely chopped. Transfer to the bowl with the nuts.
- If the feta cheese is in a whole block, break it apart with your hands and pulse it several times in the food processor until you have feta crumbles. (Note: if you’re starting with crumbled feta, skip the food processor and add it directly to the filling mixture.)
- Stir together the filling until it’s well combined.
Though this may look like some chef-inspired magic trick, filling, rolling and tying off the roast, is actually VERY STRAIGHTFORWARD. Anyone can do it.
How to stuff, roll and tie butterflied leg of lamb
- Season the butterflied lamb on both sides with salt and pepper.
- Lay the lamb fat side down.
- Spread the spinach feta and walnut filling evenly over the meat.
- Start with the short end of the lamb and begin rolling up the flap.
- Roll the meat completely and finish with the end flap tucked underneath the lamb. (tuck any filling that has fallen out, back into the rolled leg.)
Note: Pressing too hard will squeeze the stuffing out of the lamb. Too loose and the stuffing will fall out and the lamb won’t hold it’s shape.
Tying the stuffed butterflied lamb
- Cut about 6 pieces of kitchen twine into 20″ lengths.
- Wrap a piece of twine around the leg and tie it securely with a knot.
- Continue in this fashion with a piece of twine every 1 1/2 to 2″ apart up the length of the stuffed lamb leg.
- Turn the roast 90° and tie it again with one or two more pieces of string.
- Trim the ends of the string.
- Secure the tied butterflied roast onto your rotisserie assembly.
How to set up the grill for indirect rotisserie cooking
Set up your grill for indirect heat and preheat it to about 400°F. We have an old Weber Genesis gas grill and we lit the far right and far left burner, leaving the center burner off completely. This creates and even, all around heat that will gently roast the meat on all sides without any hot spots.
Our usual set up is to remove the grates on the grill and set a pan beneath the roast to catch any juices or filling that may come out as the meat roasts.
What’s the cooking time for rotisserie leg of lamb?
It depends on how large your butterflied leg of lamb is and what degree of doneness you prefer. This particular leg of lamb was nearly 6 pounds, however it was about 5 1/2 after I trimmed it of the excess fat and removed that spare flap of meat.
At 400°F, it took about 1 1/2 hours to reach our desired medium rare doneness.
However, to be sure, I highly recommend using a good quality instant read thermometer.
This is our go to Instant read thermometer. It’s reliable, easy to use, has an intuitive backlight for night time grilling and it folds away in the drawer — so the probe won’t inadvertently stab you. It’s not the cheapest one on the market, but for my money, it’s the best. In fact, I believe in it so much, I’m an affiliate.
Keep in mind that the end pieces will naturally be more cooked and the center of the roast will be more rare.
I like my lamb medium rare, but I know everyone has their own preferences. Here’s a handy guide to determine what temperature to cook your lamb for the perfect doneness.
Degrees of doneness for rotisserie lamb
|Temperature||Degrees °F & °C|
|Medium-Rare||120° to 125° F or 49° to 51° C.|
|Medium||130° to 135° F or 54°C to 57°C.|
|Medium-Well||140° to 145° F or 60°C to 63°C.|
|Well||Over 150° F or 65° C.|
I don’t recommend cooking stuffed leg of lamb too rare. The meat will be too chewy and there’s more risk for bacteria and any fat that might be towards the center will be congealed.
Save the “rare lamb” for chops or racks instead of a rolled stuffed lamb roast like this.
Stuffed rotisserie lamb FAQ’s
YES! Instructions are in the recipe card below.
Yes. You can make the stuffing and trim and butterfly the leg of lamb a day ahead of time. You can stuff, roll and tie the lamb several hours in advance and keep it refrigerated until about 1/2 hour before putting it on the rotisserie. Remove it from the refrigerator to take the chill off before grilling.
You can keep leftovers in the refrigerator for up to 5 days.
Preheat the oven to 300° F. Place the lamb on a foil lined baking sheet and gently tent another piece of foil over it. Heat for about 10-12 minutes or until the lamb has warmed through.
Yes. Wrap the meat in plastic wrap and then wrap again in freezer paper. It will keep for up to a month. Thaw before reheating.
We love this recipe to serve at family holiday events. It’s a favorite at Easter, but my French family loves lamb anytime and this bold, garlicky spinach, feta and walnut stuffed leg of lamb satisfies everyone. I hope you like it as much as we do.
What to serve with rotisserie leg of lamb:
- Homemade Scalloped Potatoes
- Garlic Herb Flageolets
- Spring Pesto Green Beans
- Tomatoes Provencal
- Mashed Cauliflower
Stuffed Rotisserie Leg Of Lamb With Spinach, Feta & Walnuts
- Gas Grill with Rotisserie Attachment
- Sharp carving knives
- 5-6 pound boneless leg of lamb
- 2 teaspoons kosher salt
- 1 teaspoon freshly ground pepper
- 2 tablespoons chopped garlic
- 1/4 cup fresh mint chopped
- 1/4 cup Italian parsley chopped
- 1/2 cup walnuts
- 1 lemon zested
- 6 ounces feta cheese good quality
- 5 ounces fresh spinach or about 1 cup of thawed frozen spinach
- 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.
- 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.
- 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:
- 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.
- 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.
- 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:
- If using fresh spinach, bring a medium pot of water to a boil and fill a medium sized bowl with ice and water.
- 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.
- 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:
- 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:
- 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.
- 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.
- 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:
- 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.)
- Lay a drip pan under where the roast will go to catch any juices or filling that may come out.
- 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.
- 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:
- 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.
- 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:
- 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:
- Preheat the oven to 425° F. Place the tied roast onto a roasting pan with 2" sides.
- 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.
- 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.
- 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.