Cut the cauliflower florets into bite size pieces and discard the stalk.
Spread the florets onto a baking tray, season with salt and pepper and drizzle with olive oil. Toss to coat evenly and then bake at 390 °F for 15 minutes.
Cut the eggs and add them to a large bowl with the baked cauliflower florets, the celery and the onion.
For the dressing: add all the ingredients to a mixing bowl or a salad dressing bottle and stir (or shake!) until a smooth consistency is achieved.
Pour the dressing over the salad and give it a good few turns with a spoon until well coated.