Wash the lentils, then place them in a pan and cover with cold water. Bring to the boil and simmer gently for 15 to 20 minutes, or until tender. Meanwhile, blitz all the vegetables, garlic and ginger in a food processor until finely chopped.
Heat enough oil to cover the bottom of a large saucepan, put it on a low heat, add the spices and fry gently for a couple of minutes. Then add the onions, carrots, pepper, garlic, ginger, coriander stalks, the chilli and all the spices and fry gently for 5-10 minutes until the onions start to soften.
Add the tomatoes, water and lentils and simmer for another 30 minutes before adding the coconut milk. Bring to the boil then remove from the heat and blend until smooth using a hand blender. Season to taste. Set aside to cool then use as required.
Any surplus sauce can be frozen to use at a later date.