I use the Pataks Korma paste for this and it's pretty much the same approach as above including the tomato soup which gives slight tomato but adds the creaminess without the cream. But I also add a fair amount of ground almond and dessicated coconut and a good slug of yoghurt. I use one of the large cans of coconut milk for korma - the msaller for the madfras above. I also add a fair amount of extra sweetening. Korma also really enjoys the slow cooker and to be honest I enjoy using neck lamb fillet which is pretty similar in price as cheap lamb in the UK but is much softer and less prone to toughness.