The meal I made with pasta, butternut squash and sage (which I described in the previous post) was yummy, but not identical in flavor to the restaurant version I was imitating. The squash at the restaurant had a little bite to it, a little tanginess that I wasn't able to replicate. I didn't know why--I thought maybe it didn't caramelize well enough or something.
But today I was skimming a cookbook and saw a recipe for something with butternut squash and balsamic vinegar, and I realized it immediately! That's what I should've added! Balsamic vinegar next time, for sure.