Maybe one you had in your family growing up, or one you make now. In my family growing up we had “healthy” Thanksgiving so I have absolutely no nostalgia for it, but I make a variation of butternut squash mac n cheese frequently (I think this year I’m going to switch to spaghetti mac because I’m having a hankering). I started with that specific recipe, which is really rich and awesome on its own, but I have gradually made it less healthy to Thanksgiving it up a bit, by making sure the milk is full fat and getting rid of nonsense Greek yogurt and adding more cheese.
As for my childhood, the day before Thanksgiving my mom would make pierogies. My Polish grandpa would visit and of her millions of siblings, she’s the only one who learned the family recipe (which was my grandpa’s version, which was loaded with bacon). After he died she decided they were too unhealthy and too much work (my brother and I both know how to do this but she doesn’t let us into her kitchen). I have made them at home but I’d rather share them with one of my siblings who’d have the right amount of appreciation.