1. Remove outer leaves and trim stalk on cauliflower. Steam for 10 minutes or microwave on High for 4 minutes (cauliflower should remain crisp). Immediately rinse under cold water. Drain
2. Combine yogurt, orange juice and tahina (if mixture is too thick, add a little more orange juice).
3. Arrange onion rings over cauliflower.
4. Top with yogurt mixture and sprinkle with orange rind. Garnish with coriander. Cut into wedges to serve.