Potato Gratin
Potatoes sliced as thin as coins, layered in a garlic-rubbed dish with cream and milk, and baked slowly until the top is brown and the middle has set into something you can cut. Do not rinse the slices — the starch that washes off is exactly what thickens the cream.
At a glance
Ingredients and method are in the app
Kitchen Pantri holds the full ingredient list and step-by-step method for Potato Gratin, checks it against what is already in your pantry, and adds anything missing to your shopping list. The app is free to use; you set up a Pantri account when you first open it.