1. Combine chicken with onion, celery leaves, carrot and salt.
2. Add water and simmer till the chicken is cooked.
3. Strain and reserve the stock. Cool the chicken and shred the meat.
4. Melt the butter in a skillet. Saute the leeks and celery till soft.
5. Add the reserved stock, tomato puree and shredded chicken.
6. Add salt and pepper to taste. Simmer for 5 minutes.
7. Serve hot, garnished with chopped parsley.

Serves: 4