While the lamb is resting, increase oven to 220°C. Line a baking tray with baking paper. Place Brussels sprout on lined tray. Sprinkle with sugar. Drizzle with butter. Season. Toss to combine. Roast, turning occasionally, for 20 mins or until tender and golden, adding the tomatoes, baby broccoli and hazelnut to the pan for the last 5 mins of cooking.