For whatever reason, I nearly always cube my butternut squash before cooking (whether it be roasting, steaming, or pan frying). It’s rare that I cook the squash whole. I think it’s because in my mind, the whole squash takes longer to cook but in the end, it’s less preparation and really, not much more time. However, when I do cook the whole squash, I steam roasted squash (putting cut side down in a roasting pan with 1/4″ of water). It’s how I saw my mother always cook acorn squash and so it stuck with me. It leaves the squash really nice and soft, perfect for a sauce!