Method:
1. Preheat oven to 180°C fan-forced. Grease a small shallow baking dish.
2. Combine celeriac, 2 teaspoons of the oil and the thyme in prepared dish. Roast, about 20 minutes or until celeriac is tender.
3. Meanwhile, place prosciutto on an oven tray; roast, until browned and crisp.
4. Segment orange over a small bowl; reserve 1 tablespoon of juice.
5. Combine orange segments, reserved juice, celeriac, prosciutto the remaining oil and remaining ingredients in a medium bowl.