Squash and Caramelized Onion Tart

An absolute G-D showstopper, which you can make entirely ahead at your own leisure, freeze, and bake day-of. It’s delicious hot or room temp. Yes, it requires a mandoline. But if you’re not averse to using them, this makes one hell of a vegetarian main or side. You can use any combo of sweet potato and squashes, just go for a pretty color variation. I prefer TJs’ Unexpected Cheddar as the cheese of choice, fwiw.