..is that You can never have too many potatoes.
There are gratins and gratins. When I was waitressing at Buitenverwaching as a student, I ate too much creamy potato gratin and gained 2kgs. Back to the gym I went.
This gratin is a bit of a cheat, because there's no cream, but I wanted something shallow and crisp, and that's all I had, with a glass of red wine and a salad.
So, A Meal for Me:
4 small to medium potatoes (I used Yukon Gold, a pale yellow fleshed variety), sliced as thinly as you can manage
Enough milk to reach the layer of potatoes just under the last wafer-thin-like covering, about a cup
1 fat garlic clove cut into very thin slices
Butter to grease the pan lightly and dot on top
Preheat oven to 400'F/200'C. Butter an oven-proof pan or dish (I used an All Clad omelette pan); the more surface area, the thinner your layer of potatoes, and the crispier they'll be. Deep narrow dish = deep narrow gratin, not enough crispy stuff. Lay your potato slices in overlapping circles starting from the outside in. Season each layer with garlic, salt and pepper. Don't put garlic on the top layer - it will burn and taste horrible. Then pour in your milk from the side (so you don't wash off all the seasoning). Put a few dots of butter over the surface and tuck a bayleaf in. Pop into hot oven and leave for about 3/4's of an hour, or until the top is seriously golden brown and the bottom layer tender.
Or consult Patricia Wells' Bistro Cooking for real gratins with real cream. They are very good.