I have not found a specific answer. it would seem, if you want to try, that you would start by leaving it on the vine as long as possible. Then ---- what?

Under normal circumstances No. They are fleshy like a pumpkin. can be carved like a pumpkin. The antique summer crookneck and probably several similar varieties do dry up and are usable as craft gourds.They do not shells as hard as gourds tho. There are some varieties of Lagenaria siceraria that have similar sizes and shapes to the butternut group.

I agree with farmerdill.
Good for eating though.