Simmer the lentils in water for 5 minutes, then drain and put to one side
Melt the coconut oil in a heavy based pan. Add the dry spices and cook over a medium heat till the mustard seeds start to pop.
Add the onion, garlic and ginger and cook gently for 3-5 minutes till the onion starts to soften.
Add the tomato puree, stock, fresh tomato and drained lentils and simmer for 15 minutes stirring occasionally and adding more water if necessary
When the lentils are soft and slightly mushy, stir through the spinach and cook for a further 2-3 minutes
Serve garnished with chopped coriander and a dollop of low fat yoghurt.