Preheat the
oven to 200C (400F/ Gas 6). Place all the vegetables with the oil in a
large baking dish. Toss the vegetables to coat with the oil. Bake for 50
minutes, or until the vegetables are crisp and tender, tossing them
every 15 minutes. Remove from the oven and sprinkle with the poppy
seeds. To make the orange dressing, whisk the ingredients together in a
small jug. Pour the dressing over the warm vegetables and toss. Top with
the Brie and serve immediately while still warm.