Preheat the oven to 200°C (180 fan) | 400°F | gas 6.
Cut the vegetables into 1.5 cm slices and arrange in concentric circles in a round baking dish.
Scatter over the oregano, then drizzle with oil and season generously with salt and pepper.
Bake for 40 minutes or until the vegetables are tender. Serve hot or at room temperature.