Aligot isn’t so much a side dish as it is a work of art. Humble potatoes and cheese are beaten together with crème fraiche until they form silky, smooth ribbons of pureed potato. It’s a deliciously hearty recipe, and it’s tempting to eat it all by itself, in the dead of winter, for its sheer comfort value. Try to hold out, though, and accompany it with a rich steak for a luxurious meal. Once you do, it will be hard to go back to regular mashed potatoes.