Gratin dauphinois

This is a dish that has frustrated me for years; I love it, but I never seemed to get consistent results when I made it. One time it would be cooked to perfection; the next time the potatoes would be cooked inconsistently, or the sauce would be too thin and sloppy, or some other disappointing variation. (And the latter seemed to happen much more often than the former. Even though I thought I was doing the exact same thing every time.)

Then, a few years ago, I came across a book called Don't Sweat the Aubergine: What Works in the Kitchen and Why, which actually explains what happens when you follow the steps of a recipe. In the section on gratin dauphinois, I found the following sentence: "It is impossible to give a recipe that you can guarantee will work every time." (What a relief to know it wasn't just my ineptitude!) The author, Nicholas Clee, then goes on to enumerate the many variables that can affect how the recipe works, including size and composition of the cooking vessel, absorption of the potatoes, etc. He also suggests - revolutionarily, for me - that you should heat all the ingredients on the stovetop before putting the gratin in the oven. He proposes using a saucepan to start, and then tipping the heated ingredients into a casserole dish to go in the oven, but when I revisited this recipe recently, I decided that this made unnecessary work and washing up, plus made the final presentation somewhat sloppy. Therefore I called one of my beloved cast iron skillets into service to do double duty. I've made gratin using this method twice in recent weeks, versus once using the cold-into-the-casserole-and-the-oven method, and the skillet/heating method wins hands down. Try it for yourself.

Gratin dauphinois
Adapted slightly from Don't Sweat the Aubergine by Nicholas Clee
This is a great dish to make when you're having company for dinner, as all the prep is done well ahead of time and then the potatoes can bake away quietly in the oven while you get on with other things. Plus anything made with this much cream is probably better shared with a group.

1 medium-sized potato per adult being served
butter
1 clove garlic, minced
salt 
1 cup/8 oz/240 ml full cream*
.5 cup/4 oz/120 ml milk*

Heat the oven to 325F/160C. Slice the potatoes thinly ("no thicker than a pound coin" - about .25-inch thick, or .5-cm; I use a mandoline for this) into a bowl of cold, salted water. They can be held like this for a bit if you have other things to do before assembly.

When ready to assemble the gratin, grease the inside of the skillet lightly with butter. Drain the potatoes and arrange in the skillet in layers, sprinkling strategically with salt and bits of garlic. Continue until you have used up all the potatoes.

Mix together the milk and cream in a small jug or measuring cup and pour over the potatoes, until the liquid is level with the top layer. If necessary, add more milk to ensure that this happens.

Place the skillet on the stovetop over medium heat and leave until liquid is bubbling around the edges and you can feel warmth coming from the potatoes when you hold your hand above the skillet. (I usually put a lid on the skillet to help this process along.)

When the gratin is heated through, remove the lid (if using) and place the skillet in the oven uncovered. Leave to cook for 1 - 1.5 hours, or until the surface has browned and the liquid has reduced and thickened.

In my experience, this holds together better and slices more neatly if you can let it sit for about 10 minutes after coming out of the oven.

Serve directly from the skillet.


* These amounts should provide enough liquid to cover about 4 potatoes' worth of slices, insofar as it's possible to predict with this recipe.