Combine the beetroot, garlic and olive oil in a small baking dish. Cover with foil and roast at 180°C for 45 minutes or until the beetroot is tender. Remove the beetroot from the baking dish, saving any pan juices. Cut the beetroot into quarters and place in a serving bowl.
Combine the vinegar and mustard in a small bowl. Add the pan juices and season to taste with salt and pepper.
Toss the orange segments, olives, onion and rocket with the beetroot. Pour over the dressing and toss again just before serving.
Did you know?
*If you buy beetroot with nice fresh tops, cook the leaves as you would spinach or silverbeet. They're also rich in beta-carotene. *Beetroot, like Brussels sprouts, contain a substance that can hinder thiamin absorption – but this won't be a problem for anyone with a well-balanced diet.