When I bake pumpkins in the fall....yes, I'm old school and I still "store nuts for the winter", I usually buy a couple bushels at a time and bake and freeze them all for pies.  What I do is freeze several in ice cube trays and once frozen pop them out and into a bag.  A couple or three pumpkin cubes are just about right for a runny gsd......
 
Yes, buy fresh and bake or boil it yourself if you can't get it canned.