1. Cut the butterflied lamb shoulder in half. Warm a frying pan or casserole dish on a medium heat for 2 mins. When warm, drizzle in 1 tbsp olive oil and place in the lamb shoulder. Fry for 10 mins, turning halfway, till browned. Lift the lamb out with tongs and transfer it to a bowl.
2. While the lamb browns, peel and finely slice the onions. Peel and grate the garlic and ginger. Fill and boil your kettle. From this point on, follow the instructions for the slow cooker or the oven.
3. Slow cooker:
Peel the sweet potatoes and chop them into large chunks. Trim and peel the carrots, then thickly slice them.
4. Add the onions, garlic and ginger and chopped veg to your slow cooker. Add 1 tbsp ras al hanut and drop in the cinnamon stick. Drain and rinse the chickpeas and add them to the slow cooker. Pour in the tin of chopped tomatoes and 300ml hot water from the kettle. Add plenty of salt and pepper and mix well. Lower the browned lamb into the slow cooker and push it down so it’s mostly covered by the sauce.
5. Pop a lid on the slow cooker, set it to medium and cook for 6-7 hrs. For a faster stew, set the slow cooker to high and cook for 5-6 hrs, or set to low and cook for 8-10 hrs.
6. When the cooking time is nearly up, finely chop the mint leaves. When it’s cooked, taste the tagine and add more salt or pepper if you think it needs it. Lift the lamb out of the slow cooker onto a chopping board. Remove and discard any excess fat, then use a couple of forks to shred the lamb into large chunks. Add back to the slow cooker and stir. Divide the tagine between 4 warmed bowls and scatter over the mint leaves to serve.
7. On the hob:
Add the onions to the pan you cooked the lamb in and fry for 6 mins till softened and lightly coloured. You shouldn’t need to add any extra oil, but if the onion starts to stick add 2-3 tbsp water.
8. Add the garlic, ginger 1 tbsp ras al hanut to the pan and fry, stirring, for 1 min. Pour in the tin of chopped tomatoes and 600ml boiling water. Drain the chickpeas and add them. Stir to mix, then add the browned lamb. Cook for 1 hr.
9. While the lamb is cooking, peel the sweet potatoes and chop them into large chunks. Trim and peel the carrots and thickly slice them. When the lamb has cooked for 1 hr, add the chopped veg and cook for a further 1 hr till the meat is tender.
10. Lift the lamb out of the pan onto a chopping board. Remove and discard any excess fat, then use a couple of forks, shred the lamb into large chunks. Add it back to the pan and stir to mix.
11. Finely chop the mint leaves. Taste the tagine and add more salt or pepper if you think it needs it. Divide the tagine between 4 warmed bowls and scatter over the mint leaves to serve.