- Preheat the oven to 200ºC fan oven/220ºC/gas 7.
- Put one tablespoon of the oil in a roasting tray and add the sausages and onions. Place in the oven for 35 minutes.
- Cut the polenta into chips. Put another tablespoon of oil on another roasting tray and roll the polenta chips in the oil. Sprinkle over the parmesan. Season with salt and pepper and distribute things evenly. Roast in the oven for 30 minutes.
- 20 minutes before the end of the cooking time, put the tomatoes on a tray, sprinkle with oil and season with salt and pepper.