Preheat the oven to 200°C /400°F /gas mark 6. Line a roasting tin with baking parchment. Chop the vegetables into bite-sized pieces and place in a large bowl. Dress in a few tablespoons of light olive oil, just enough to coat. Cover the vegetables with any robust herbs or garlic and season well. Place in the hot oven and reduce the temperature to180°C/350°F/gas mark 4. Move the vegetables every 10 minutes, until caramelised on the outside and softened on the inside, but holding good shape. Remove and adjust the seasoning. Splashing a tray of roast pumpkin with sherry vinegar halfway through cooking will add to its caramelisation and depth.