Layers of thinly sliced potatoes smothered in a cheesy cream sauce topped with an extra layer of cheese, and baked until golden and bubbly. Classic potatoes au gratin is made with humble ingredients, can be made ahead, and is a budget-friendly way to feed a crowd!
Prep ahead by assembling the casserole then baking it covered for 30 minutes. Cool completely and store in fridge. When ready to serve, bring to room temp and bake uncovered 20-30 minutes.