Wash the pumpkin thoroughly and remove the skin and seeds.
Cut the pumpkin into small pieces.
Finely chop the onion.
Melt the butter in a pot and sauté the onion.
Add the pumpkin and sauté together.
Pour water or broth and boil until the pumpkin is cooked.
Turn off the heat and blend the ingredients smoothly with a hand blender.
Add milk or fresh cream, stir well, and heat once more over low heat.
Season with salt and pepper to taste and serve.