When I rotated our cold room produce there were a few winter squash that were reaching the end of their storage life. The Hubbard, butternut and buttercup squash that were starting turn around the stem ends were roasted, puréed, dehydrated, ground into powder and moved to dry goods storage.
I find that dehydrated wInter squash re-hydrates well and can be used in any dish that calls for puréed squash or pumpkin. I have also found that most winter squash is interchangeable in pies, quick breads, soups and stews.
The process I use to create squash powder can be found in the images below.