If you sugar it, like rhubarb, it'll start to pull the juices and then ferment.....once it does (not left to go rotten, I mean, ferment as in making booze) then you can add vinegar and spices and turn it into chutney.
On the other hand, you can just roast it, hard as it is, and it will cook. (mind and add a wipe of oil and keep it covered so that it softens as it cooks and doesn't just stick and dry out) You can breadcrumb some once it's cooked. Bit like green tomatoes fry well, kind of thing.
Works in stew like ratatoule too and can be boiled up and whizzed for soup. Still needs flavoured though.
Not 'ticulary fond of pumpkin and squash to be honest. Bit like marrow; looks good but just sommat big and bland. It definitely needs flavour added. Whether you roast that in or spice, season or sugar that in, it needs something.
If it's not 'that' hard it'll cook like butternut squash.
M