Boil water and tea bags in large saucepan for 5 minutes. Remove tea bags. squeezing the excess liquid into the pan. Add the cauliflower to the tea, cover and simmer for 15 minutes or until tender. Drain, reserving 1 cup of the liquid.
In small pan, saute the onions and celery in the butter until the onions are clear. Put in a blender with the cauliflower, salt and pepper, and the reserved cooking liquid.
Blend until smooth and serve.
For thinner soup, reserve and add more liquid; for thicker soup reserve and and add less.