Add the vegetable oil to a pan on a medium heat and then add the onions. Cook until slightly golden and translucent.
Add the garlic and ginger & garlic paste and cook for 1 minute.
Add 2tbsp of Tandoori Lamb mix, the tandoori masala, salt and chilli powder. Add a dash of the stock to stop the spices from burning and cook for 30 seconds.
Add the tomato concentrate mix and cook for 4-5 minutes - stirring occasionally.
Add the stock in quarters. You want the curry base to soak up the stock before adding more.
Once you've added all the stock, add the pre-cooked lamb, coriander stalks, Naga chilli (if using) and mango chutney. Simmer for 5 minutes.
Add the quartered tomato, lemon juice and kasuri methi. Cook for 1 minute.
Serve with a garnish of freshly chopped coriander and sliced red chilli.