Ingredients (about 300 ml sauce)2 tbsp rapeseed oil1 medium onion, finely sliced (about 120 g)2 small tomatoes, finely chopped (about 120 g)3 cloves garlic, finely chopped or crushed2 cm piece ginger, finely chopped or grated1 fresh green chilli, sliced (deseed for milder heat)1½ tbsp ground coriander1 tsp Kashmiri chilli powder (or to taste)½ tsp ground red pepper or extra chilli powder (optional, for more heat)½ tsp turmeric½ tsp cumin powder½–1 tsp garam masala½ tsp salt (or to taste)1 tbsp creamed coconut, finely chopped2 tbsp coconut milk powder2 tbsp palm vinegar150–180 ml water (enough to reach sauce consistency)MethodMake the masala baseHeat the rapeseed oil in a pan on medium heat.Add the sliced onions and cook slowly for 8–10 minutes until soft and light golden.Stir in the ginger, garlic and green chilli and fry for 1–2 minutes until fragrant.Build the spice layerAdd the ground coriander, Kashmiri chilli powder, ground red pepper (if using), turmeric, cumin powder and salt.Fry the spices gently for 30–60 seconds, splashing in a spoonful of water if they start to catch.Add tomatoes and sournessAdd the chopped tomatoes and cook for 5–7 minutes, stirring, until they break down and the oil begins to separate from the masala.Stir in the palm vinegar and simmer for 2–3 minutes so the sharpness softens slightly.Finish with coconutAdd the creamed coconut, coconut milk powder and about 150 ml water.Stir well and simmer gently for 5–10 minutes until smooth and slightly thickened, adding extra water if needed to reach roughly 300 ml of pourable sauce.Stir in the garam masala, taste and adjust salt, vinegar or chilli to balance heat, creaminess and tang.This sauce can be used straight away with fish, prawns, chicken or vegetables, or cooled and kept in the fridge for a couple of days and reheated gently with your chosen main ingredient.