Heat oil in a large soup pot. Add onion & celery & saute over moderate heat until golden. Add potato, carrots, water, bouillon cubes, celery leaves, tomatoes & cumin. Bring to a boil, reduce heat, cover & simmer for 15 minutes. Add cauliflower & continue to simmer for 10 minutes more. Season to taste. Remove from heat & let soup cool. Refrigerate overnight to develop flavour. Just before serving, heat soup & add remaining ingredients. Simmer for 10 to 15 minutes. Add more water if needed. Serve with 3 to 4 matzo balls per bowl.
Nava Atlas, "Vegetarian Celebrations"