- Heat oil in a large soup pot.
- Add onion and celery and saute over moderate heat until golden.
- Add potato, carrots, vegetable broth, celery leaves, tomatoes and cumin.
- Bring to a boil, reduce heat, cover and simmer for 15 minutes or until vegetables nearly tender.
- Add the cauliflower and continue to simmer for 10 minutes more or until crisp tender.
- Season to taste with salt and pepper.
- Remove from heat and allow the soup to stand off the heat for 2 hours or longer to develop flavor.
- Just before serving, heat soup and add cabbage, basil and scallions.
- Simmer for 10 to 15 minutes.
- Add more water if needed and adjust seasonings
- Serve with 3 to 4 matzo balls per bowl.