Heat the oil in a large pan and add in the red onion and cook for around ten minutes until softened.
Stir in the cumin seeds, garlic and ginger and cook for another minutes until fragrant.
Add in the tomatoes, turmeric and coriander and season with salt.
Cook until the tomatoes have broken down and softened which will take around 15 minutes.
Pour this into a blender and add in the yoghurt. Blend until smooth.
Return the mixture to the pan. Add in the chick peas with the water and cover and simmer for around for 5-10 minutes.
It is normal for the oil to separate.
Stir in the spinach and stir until wilted.
Add water if required.
Serve on a bed of rice with warm naan bread.