Wash cauliflower and break into florets. Peel carrot and chop into medium size pieces. If I have time, I parboil the cauliflower for 2 minutes, just to soften it SLIGHTLY, but most times I skip this step. Personally, I prefer it raw.
Working in batches, whiz cauliflower florets in a blade food processor until the pieces are about the size of cooked rice. Do the same with the carrot. Mix the two veggies together in a bowl.
Chop green onions using both the white and green parts. Add to the veggies.
Add celery seed. If you associate potato salad with a really celery taste, use more. If not, use less.
Add mayo or salad dressing and fold to combine. Refrigerate to blend flavors. To fancy it up, add crumbled bacon slices and hard boiled egg slices on top, just before serving.