Wash the pumpkin, rub dry and quarter it. Remove the seeds and cut the flesh into thin slices. Peel and wash the potatoes and, depending on their size, cut them in half lengthwise. Preheat oven (electric cooker: 225°C/circulating air: 200°C/gas: level 4).
Wash the thyme and pluck the leaves from the stems. Finely grate the parmesan. Mix cream and half of the parmesan. Season with salt, pepper and thyme.
Mix the pumpkin and potatoes with the oil on a baking tray. Add thyme cream, sprinkle with the rest of parmesan and bake in a hot oven for 40-45 minutes.
Wash the tomatoes and dab them dry. Add 20 minutes before the end of the cooking time, cook along. Serve on a tray.