Wash the pumpkin under hot water, then cut it in half, remove the seeds and cut the two pumpkin halves into slices as thick as a thumb.
Preheat the oven to 200 degrees circulating air.
Peel and quarter the onions. Dice the cheese. Wash the rosemary and pluck it into pieces. Arrange the pumpkin in a circle in a baking dish and garnish with the onions. Salt and pepper. Spread the cheese cubes and rosemary evenly over the top. Pour the vegetable stock and drizzle with the olive oil. Bake in the oven for 30-40 minutes until the pumpkin is easy to prick and the cheese has turned a nice golden brown color.