Made today, along with steak, broccoli, cherry tomatoes and corn:
Tried out my new mandoline, and thought it wasn't working, because it was so smooth and easy. Then I noticed the slices of potato beneath it, and - triumph! Watch your oven (it might dance around the room): mine took significantly less than the recipe suggested to cook.
A very creamy, cheesy, smooth concoction. We (hi, Mom!) used less than half the amount of onions. More might increase the grease quotient.