Cut pumpkin open and remove seeds. Cut pumpkin into one-inch cubes. Slice onion, and sauté for a few minutes, then add the pumpkin. Sautee for about five minutes, stirring, and then add a cup of water, put on a lid and let it simmer for forty to fifty minutes, until the pumpkin is tender. At this point some of the pumpkin can be mashed to thicken the broth. Add some more water to the onion-pumpkin mixture to make it soupy. Heat and season with salt, cinnamon, and nutmeg. The soup may be garnished with croutons. Can also be made with winter squash.