Preheat oven to 210C. Line baking tray with baking paper.
Place the cauliflower florets in a single layer on the baking sheet. Drizzle with olive oil and sprinkle with nutmeg, salt and pepper. Toss to coat and then spread the cauliflower out on the baking sheet. On a separate tray, place hazelnuts on a baking sheet. Set aside.
Roast the cauliflower for 30-35 minutes or until golden brown and cooked. At the last 10 minutes of baking, place the hazelnuts in the oven as well and sprinkle thyme leaves.
Arrange cauliflower on a serving dish, sprinkle hazelnuts over the top. Shave fresh truffle, drizzle with truffle oil and parsley to serve.