Place cut-side-down on a cookie sheet and bake at 350F for 20 to 45 minutes, until the squash can be pierced easily with a fork but be careful not to burn. In the skin starts turning brown, it's done. Set aside to cool until it is safe to handle. Scoop out seeds and stringy matter and discard. Then scoop out flesh and transfer to a blender.
Add vegetable broth, starting with 1/2 cup, adding more as necessary until the soup becomes thick and silky but totally pureed.
Add curry powder to taste (all curries are a little different, some stronger than others). Gently reheat on the stove over low heat, adding salt to taste if desired. You can also add cayenne or hot sauce for a spicier curry flavoring. Nutritional Information