Heat the oil in a large pot over a medium heat.
Once hot, add the sliced onions and sauté for 4–5 minutes, stirring occasionally, until they begin to soften and turn lightly golden.
Place the lamb into the pot and cook for 6–8 minutes, stirring regularly, until the meat changes colour and is lightly browned on all sides.
Add the spices and mix thoroughly to coat the lamb evenly. Continue cooking for 3–4 minutes, stirring frequently to prevent the spices from sticking or burning.
Pour in the pureed tomatoes and stir well. Cook for 5–6 minutes over a medium heat, stirring occasionally, until the tomatoes have reduced and the oil begins to separate from the masala.
Pour in the water and stir to combine. Cover the pot with a lid and allow the lamb to simmer over a medium heat for 20-25 minutes.
Add the chopped turnips and spinach, stirring gently to combine them with the lamb and gravy.
Cover the pot again and continue cooking for 15–20 minutes, or until the turnips are tender and the lamb is fully cooked.
Finish by adding the freshly chopped coriander and stirring gently to distribute it throughout the curry.
Serve hot with freshly made chapati, naan or rice.
