Wash the sweet pumpkin thoroughly and cut it in half.
Remove the seeds and pulp, then steam for about 15 minutes.
Scoop out some of the flesh from the steamed pumpkin and mash it.
Finely chop the onion, carrot, and broccoli.
Melt butter in a pan and sauté the vegetables.
Mix the mashed pumpkin, sautéed vegetables, milk, salt, and pepper.
Fill the pumpkin skins with the mixture and top with cheese.
Bake in the oven at 180°C for 15 minutes.
Remove the finished sweet pumpkin gratin.