Last year we cubed our butternut squash, laid the pieces on trays and froze them and then bagged them up into helping sizes. We steamed our squash direct from frozen in one of those collander-type steamers that fits into a regular saucepan and the butternut squash tasted the same as it did when used fresh. The only thing I have forgotten is how long do I have to leave the pieces on the tray before I can bag that lot up and moved on to the next batch?
The other thing of note is that we got 3 enormous squash, a photograph of which I posted earlier on, and I have opened one of these up and the flesh looks perfectly edible once you have peeled all the green outside off. We have also tasted it and it tastes OK
Shambasarfi