New York Times

Cheesy Hasselback Potato Gratin

This golden and glorious mash-up of potato gratin and Hasselback potatoes, from the acclaimed food science writer J. Kenji López-Alt, has been engineered to give you both creamy potato and singed edge in each bite. The principal innovation here is placing the sliced potatoes in the casserole dish vertically, on their edges, rather than laying them flat as in a standard gratin, in order to get those crisp ridges on top. Allow extra time for the task of slicing the potatoes, for which it's helpful to have a mandoline or food processor (though not necessary, strictly speaking). And do buy extra potatoes, just in case; you want to pack the potatoes tightly and keep them standing up straight.