To Prepare Cauliflower: Preheat oven to 475 degrees. Chop cauliflower. Arrange cauliflower on a cookie sheet. Drizzle olive oil on top and give a quick stir till all cauliflower is coated. Roast for 10 minutes, or until tops begin to brown and cauliflower is tender with a slight crunch.
To prepare dressing: Peel and quarter oranges (I used blood oranges). Blend all ingredients in a high powered blender until smooth and creamy. Add some Orange juice to thin if necessary (I did not do this).
Blend the dressing with the roasted cauliflower and season with salt if desired.