Peel the onion and garlic. Finely dice together with the pepper.
Fry them together in a hot saucepan, then deglaze with the vegetable stock. Add canned beans including the liquid. Clean the leek, cut into fine rings and add to the soup. Let simmer for about 30 minutes, stirring every now and then.
Before serving, add the spring onions, cut into fine rings, and the chives and let them steep briefly. Season with salt, pepper and yeast paste. Serve hot.