My best guess is to wash the pumpkin, gut it, then either grate the meat and top their greens with it or cube them into something manageable. You could also maybe steam it, or make a squash-like bisque for them if you wanna be fancy Thanks for giving me a second use for the pumpkins after my kids are done carving them!
If you have little ones, blend the meat and seeds too and let them eat it however you want, on food or alone. For larger ones, just break it open and let them have it. Don't boil it, you will loose any good stuff in it, like nutrients. I have placed them in the microwave for just a few minutes to spoften them a bit.
IMHO whole pumpkins are a pain, I buy canned pumpkin when it's on sale in the fall and keep it over the year.. blends in with favorite foods and it is MUCH more aromatic than whole.