150ml soured cream or creme fraiche (I use the low fat version)
Here’s what you do:
Step 1 - Melt the butter in a large pan with the oil. Adding oil at this point helps to ensure that the butter does not burn. Add the vegetables and apple and sweat them down for at least 10 minutes (20 minutes is better as it seems to release more flavour). Stir every couple of minutes and add a little water if you think that the vegetables are going to stick.
Step 2 - Stir in the cumin seeds and cook for one minute. Pour in the stock and add the bay leaf, lemon juice and seasoning. If you are using Marigold vegetable boullion this is already quite salty, so check before you add salt. Boil and the simmer for 30 minutes.
Step 3 - Leave the soup to cool slightly and then puree the soup and add the sour cream/creme fraiche if using.