Clean and peel the carrots and celery. Cut carrots in half and cut into longer pieces. Cut celery into quarters and cut lengthwise into pieces about 1 cm thick. Clean, wash and cut leek diagonally into thick rings.
Cook the carrots and celery for about 5 minutes in boiling salted water. Take them out and let them drip off. Cook leek in boiling water for about 1 minute. Remove and also drain. Peel and slice the onion.
Shape the sausage meat into medium sized balls with moistened hands. Heat the oil in a pan and fry the meatballs for about 5 minutes. Add onion, carrots, celery and leek and fry for approx. 5 minutes.
Season with salt and pepper. In the meantime season the crème fraîche with salt, cayenne pepper and curry. Put a dash of curry crème fraiche on the pan and serve garnished with parsley.