Heat oil in a large saucepan.
Add onion and cook slowly until caramelised, nice golden brown. If you are using leek, just cook until soft, not brown.
Add ginger, garlic, mustard seeds and coriander seeds and stir in quickly.
Add turmeric and salt to taste and stir.
Add chopped tomatoes and cook at least 20minutes. This needs to cook that long to make a rich sauce. If you cook for less time, it will not have the full flavour. Add water if sticking.
When oil comes to top of the tomato sauce, add in coconut cream.
Cook for 5-10 minutes until the sauce is all well integrated.
Add the chickpeas and warm through.
Put in the vegetables and fresh coriander if using. Heat until sauce begins to bubble, then 5 minutes more. Turn off heat and leave to sit, the vegetables will slowly cook with the residual heat.
Serve with easy cook brown rice, spelt naan or spelt chapatti.