Finely chop the onion and fry together with the mince. Then pour into a saucepan, add approx. 900 ml of vegetable stock and stir.
Lightly fry the leek. In the meantime, drain the white beans and puree with the remaining vegetable stock. Add the fried leek and the bean puree to the mince and simmer for about 30 minutes. Then season.
The pureed beans create a creamy consistency that is in no way inferior to a cheese and leek soup.