Wash the pumpkin thoroughly, remove the seeds, and cut into small pieces
Slice the onion thinly
Melt butter in a pot and sauté the onion
Add the pumpkin and sauté together
Pour in water and boil until the pumpkin is cooked
Blend the cooked pumpkin and onion until smooth using a blender
Pour back into the pot, add milk and salt, and heat