I have two way/ options how to work with them. First is lazy but perfectly okay for freezer. Second is more fancy and great for immediate consumption.
Cut them in a half, scoop out seeds (you can rost them - yummy snack), place them on the baking paper and bake for about 40 minutes in the owen (356° F/ 180° C). I spray a little olive oil over the top, but it's not necesary.
If you want more flavor you can lard them with garlic. Make a little whole by knife (be careful) and place glove of the garlic inside. Then bake same way.
After baking let them cool down little bit and scoop meat out (I didn't use skin, but for example Barborka do). Place them to the mason jars or plastic bag and let them cool down completely. Then put in the freezer.
When it's time for pumpkin puree soup, I just grab one of those bags/jars and place them in the pot, add water, carry, onions and prepare a soup. Super fast and super easy....
Cut pumpkin to the cubes (remove skin if you want, I do) and bake them with garlic and 1 Tbs of olive oil. I usually add chilli powder for another kick. Again in the owen (356° F/ 180° C) for about 20-30 minutes - mix them in the middle of the time. Then add walnuts and bake again for another 5-10 minutes.
Remove from the owen and serve with Feta cheese (if you can tolerate cheese), if not try macadamia ricotta instead.