Thoroughly wash and clean the celery bulb and cut into small cubes. Heat the oil in a saucepan, stew the celery cubes in it for 10 minutes, dust with flour and add the broth. Salt and pepper lightly, simmer for half an hour.
Beat the egg yolks with the cream and use them to thicken the soup. Garnish with toasted white bread cubes and chives before serving.