If it is orange inside, you can use it in any recipe that uses pumpkin or butternut and most that use sweet potato. Easiest way to cook it is if you manage to chop it apart, hollow out the seeds poke a fork inside a few times and then I'd start by microwaving on high for 5-7 minutes. No water! You may want to cover it with plastic wrap. Scrape out the flesh when it is soft.
You can also bake in a regular oven, or cube and boil.
The Vegan Vietnamese place I go to makes an excellent soup with it, not creamy. I looked for a recipe but didn't find one -- did see a picture that looked close.