Wash the cauliflower and cut into small florets. Peel the onion, carrot and potatoes and cut into small cubes.
Leave out the vegetable margarine in a large saucepan. Add the onion and sauté until translucent. Add the carrot and potatoes and fry for 3 minutes. Add the cauliflower, the vegetable stock and possibly some turmeric. Simmer gently for about 15-20 minutes.
Skim 2 soup ladles of vegetables and set aside. Puree the rest of the soup with the hand blender. Add the skimmed vegetables back and season with salt and black pepper if necessary.