Peel, wash and dice the potatoes, celery and carrots. Clean and wash the leek and cut into rings. Put all the vegetables in a saucepan, pour the stock over them and bring to the boil. Simmer on a low heat for approx. 20 minutes. Season to taste with pepper and marjoram and puree. Scatter marjoram leaves and colored pepper over the top.
If you like, add 50 g of shrimp per person (then calculate 1 point more) or 50 g of reduced-calorie sausages (4 points more)