Prepare: Separate cauliflower florets from stem, cut stem into small pieces. Remove the peel from the potatoes, dice.
Soup: put vegetables, soup and juice of one lemon in a frying pan, bring to boil, reduce temperature and simmer on low heat with lid closed for about 20 min until soft. Remove from heat. Set aside a few nice cauliflower florets for garnish. Grind the rest in a hand mixer. Mix in sour cream and curry. Set aside to cool for at least 2 hours.
Serve: Fill soup into dessert bowls or plates. Cut cauliflower florets set aside into slices, place on top, sprinkle a little curry powder on top.
Tip: Instead of cauliflower, use broccoli, fennel or celery.