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This recipe is from the talented Gísli Matt, chef and owner of acclaimed Slippurinn in Vestmannaeyjar (the Westman Islands), Iceland. It is featured in his new cookbook Slippurinn - Recipes and Stories from Iceland, which can be purchased through Gísli Matt directly, or through Phaidon.


  • Lamb shoulder or leg of lamb (choose organic, sustainable lamb)
  • 1 Long sugar kelp (appx 1m/1yard)
  • 100g fresh Arctic thyme (other herbs can be used)
  • 100g fresh Lovage (other herbs can be used)
  • Saltverk Flaky Sea Salt


  • 300g rhubarb jam 
  • 150g brown sugar with molasses
  • 50g apple cider vinegar
  • 30ml fish sauce 
  • 45g soy sauce 
  • 100g garlic 
  • 6g dried, smoked chile flakes
  • 400ml lamb stock 
  • 4g sea salt

Before beginning, the lamb should be brined.  Best is to keep the lamb shoulder in 3% salt brine (30 g sea salt per liter of water) for at least 8 hours, or up to 16.

Then, the rhubarb BBQ needs to be made.  Slowly sauté the garlic and the chile flakes with just a touch of oil, then stir in all the remaining ingredients and let the sauce reduce on medium heat for about half an hour. Cool it down so it becomes a glaze.

Next, the lamb.  First tie up the leg of lamb with butcher’s twine for even cooking results.  If using a lamb shoulder, debone half, and tie it up the same as you would with a leg.  Glaze the lamb in the rhubarb glaze.  Chop up the herbs and rub the herb mixture into the lamb as well.

Wrap sugar kelp as tightly as possible around the lamb and then wrap it with aluminum foil. Cook until lamb is medium rare to medium.  Ideal heat would be 80° to 90°C (175° to 200°F) for about 20 hours.

Serves: up to 8, depending on size of lamb

Image courtesy of Gísli Matt, @gislimattand Gunnar Freyr Gunnarsson, @icelandic_explorer


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