Sweat the onion and pumpkin in butter or olive oil and do not cook too soft. Put aside.
Bring the water and milk with the spices to the boil, stir the polenta into the boiling liquid with the whisk, bring to the boil and let it swell over a low heat (note the package insert, this can take between 3 to 15 minutes). Stir again and again, otherwise it will burn!
Season to taste with the main course as spicy or mild. Before serving, fold in the pumpkin cubes (heated again) and flakes of butter.
If you like, you can also stir in Parmesan as in the classic variant (I find it too dominant as an accompaniment to dishes with sauce, it goes better with briefly roasted meat).