preheat oven to 400. cut cauliflower into bite sized pieces. place on ungrased cookie sheet and drizzle with olive oil. place in oven and roast until golden brown and tender, about 20-30 minutes. Remove from oven and let cool while cooking th4e rest of the soup.
in large stockpot bring sweet potatoes, onion, garlic and water to boil. Salt and stir. Reduce heat and allow the remain at constant simmer until potatoes are tender. Add in cauliflower and divide into 2 parts.
blend one part soup in blender until smooth. combine with second part soup and stir. salt to taste.
