Heat 1 tablespoon of olive oil in a Dutch oven over medium heat.
Add lamb and sear each side for 1-2 minutes until browned. Remove from pan.
Add the remaining 1 tablespoon of oil, then add the onion, carrot and celery and cook for 3-5 mins until soft.
Add garlic, and fennel and cook a further 3 minutes.
Stir through harissa paste if using.
Add tomatoes and chicken stock. Bring to a simmer.
Once simmering, add in the pearl barley. Bring to the boil then reduce heat.
Return the lamb shank meat back to the dutch oven.
Cover, simmer over low heat for 1 hour 30 minutes - 2 hours, or until soup is thick. Lamb should be falling off the bone, or easily shredded with a fork. Stir every so often so the barley doesn't stick to the bottom of the pan.
Remove lamb from soup with a slotted spoon and use two forks to shred the shanks. Place back into cast iron and stir well.
Stir through the lemon juice and lemon zest.
Spoon into bowl, then add your desired toppings.
Video
Notes
Browning the meat - don't skip this step! This locks in the flavour and provides extra flavour to the dish. When putting the meat back in the soup, make sure you include all those gorgeous juices! Sautéing the Mirepoix (carrot, celery and onions) - if the vegetables start sticking to your pan, add extra olive oil or a splash of water to loosen all the crusty bits at the bottom of the pan. SimmeringTips - simmer over a low heat. You will need to stir regularly to ensure the barley doesn't stick to the bottom of the pan. Nutritional Information - doesn't include garnish options.