Peel, wash and chop the carrot and celery. Clean, wash and cut leek into rings. Peel and roughly chop the onion. Wash and clean the tomatoes and cut them into pieces.
Heat 1 tablespoon of oil in a saucepan. Fry the vegetables, tomatoes and onion for about 5 minutes. Deglaze with 1 1/4 litre of water, add 1 teaspoon of salt, bring to the boil and simmer at low heat for about 45 minutes.
Clean and wash the green beans, cut them into smaller pieces and cook in boiling salted water for 10-15 minutes until firm to the bite. Put flageolets in a sieve, rinse thoroughly and drain. Wash parsley, dab dry, remove coarse stalks and chop leaves finely.
Pour broth through a sieve into a pot, bring to the boil with the flageolets and simmer for about 2 minutes. Season to taste with salt, pepper and some sugar. Heat 1 tablespoon of oil in a coated pan.
Fry the cabanossi for 1-2 minutes on each side until crispy. Remove the green beans, briefly sprinkle with cold water and add to the flageolets in the pot. Arrange soup and fried cabanossi in preheated cups, sprinkle with parsley.
Rustic baguette tastes good with it.