This is my variation of an old NY Times Thanksgiving recipe from 2003. It's excellent (which in Thanksgiving terms means it won't alienate anyone), foolproof, and also different enough that nobody else will be bringing it. I'm quite sure the cooks here can take the recipe apart and redesign it for a slow cooker or Instant Pot without the need for added water or attention, but even made as described it's a breeze.
3 lb delicata or butternut (or acorn: see notes) squash
3 TBS butter
3 TBS bruised and finely chopped rosemary
3 C apple or pear cider
1 tsp balsamic or apple cider vinegar, to taste
Freshly ground black pepper.
Peel squash, halve lengthwise, and remove seeds with spoon. If using delicata, slice into half-moons 1/2-inch thick; if using butternut, dice into 1/2-inch chunks.
Melt butter in a 12-inch skillet over low heat until foamy. Add rosemary, and cook over medium heat to flavor butter, stirring frequently, about 2 minutes. Add squash, cider, and 1 tsp salt. If squash is not covered by cider, add water until almost covered.
Bring to a simmer, and cook until squash is tender and cider has reduced to a glaze, stirring now and again, 30 to 40 minutes. Sprinkle with vinegar, and season with salt and pepper. Serve.
I prefer the texture and taste of acorn squash, but they are a pain to peel. It's made much easier by cutting them into pie-slice lobes, then peeling the skin from each one. By all means use a big butternut.
If you're going to use balsamic, then please use the real stuff! By that I mean hideously-expensive small bottles from Modena with fluid the viscosity of 90w axle oil. I've had an excellent one and also a to-die-for one for ~5 years, and they're still half-full, even though I take a taste every time I see them.
I also really like Heinz apple cider, but only the grade they sell in glass bottles. The plastic-bottle stuff is good for cleaning things. It was Heinz' second of its original 57 varieties. The first one was their white vinegar, and the glass-bottle version of that is a gorgeous neutral vinegar.