1. The night before serving, place cauliflower pieces, tomatoes, mushrooms, carrots, olives (if using) and onions in a large bowl.
2. Pour entire bottle of dressing over veggies and mix well.
3. Tightly cover and refrigerate overnight, stirring before you go to bed.
4. In morning, add cooked shrimp to veggie mixture; combine gently but thoroughly; keep covered and refrigerated.
5. When ready to serve, drain shrimp/veggie mixture well and arrange attractively on a platter.
6. Arrange hard boiled egg halves around edge of platter, grind black pepper over all, and serve.