Instructions

1. Wash and peel the potatoes.

2. Grate the cheese with a medium-fine grater, or crumble it into small pieces with your hands.

3. Heat the oven to 350 degrees F. Take one of your tablespoons of butter and grease your baking pan with it.

4. Use the mandoline to cut your potatoes into paper-thin slices. They'll look like uncooked potato chips. Put one layer of them on the bottom of your baking pan, making them overlap like fish scales. Add salt, pepper and about a third of your cheese.

5. Put down another layer of potato slices, then add another layer of salt, pepper and cheese on top. If you have enough potato slices, repeat until they're all gone.

6. Add the milk to the pan. Make sure it covers all but the top layer of the potatoes. Put the 3 tablespoons of butter on top of the gratin.

7. Bake the gratin for one hour, uncovered, but set your timer to go off after half an hour. When it does, remove the dish from the oven and use a spoonula or spatula to smush down the top layer of potatoes. This will help the dish retain its moisture.

8. Put the dish back in the oven, still uncovered. Set your timer for 15 minutes: when it goes off, add the remaining cheese to the top of the dish.

9. Put the gratin back in the oven, still uncovered. Set the timer for 15 minutes again. When it goes off, check the dish. If it's browning on the top, poke the potatoes with a fork to make sure they're tender. If they are, you're ready to take it out of the oven.

10. Let the gratin cool for 20 minutes--this allows any liquid parts to absorb into the dish. The dish will serve six.