The potato gratin
If you take an amount of potatoes, slice them thinly and layer them in a buttered earthenware dish, cover them with milk and bake until a crust has formed, you’ll have made a version of one of the most popular and luxurious dishes from the classic repertoire. Depending on your point of view it might be called potato gratin, or potato dauphinois, or as Americans refer to the dish, scalloped potatoes.
I’ve cooked intuitively – or perhaps unwittingly – every possible variant of baked sliced potato and never really known exactly what kind of potato dish I was making. So I’m prodding under the surface of the crusty gratin to find out more…
In matters of French cuisine it’s always good to consult the Larousse Gastronomique by Prosper Montagné, my 1961 edition gives immediate insights into confusions of sliced-baked-potato nomenclature. We learn that potatoes à la daupinoise (or pommes de terre dauphinoise) is also called gratin de pommes à la dauphinoise. The source also describes the term gratin as a thin crust formed on the surface of certain dishes when they are browned in the oven or under the grill. The term is extended to denote a certain method of preparation such as macaroni au gratin. A la dauphinoise means from the Dauphiné region of France, near the Alps. The regional cookery shows a marked predilection for gratin dishes, which apart from macaroni and potatoes might include chopped porridge, swedes, cèpes, and crayfish tails. So our classic recipe for sliced baked potatoes is both a gratin and a dauphinois, perhaps this is why it is most commonly referred to as gratin dauphinois.
We should take care not to confuse the many potato dishes that borrow terms or methods: a Dauphiné potato is potatoe puree with egg and choux pastry formed into balls and deep fried, potatoes gratinè can be a dish of boiled sliced potatoes baked or grilled with cheese on top whereas, pommes de terre gratinées is mashed baked potato put back into its skin, covered in cheese and grilled. A variant of the dauphinois which often crops up in my cooking is pommes de terre à la savoyarde, where the milk is replaced by stock.
On the matter of how to cook a dauphinois potato, a quarrel rages in France as to what makes a true gratin dauphinois, perhaps rather like the squabbles in Spain over the making of an authentic paella valenciana. Montagné is clearly following Escoffier’s classic method and instructs us to moisten the sliced potatoes in boiled milk, in which has been added a beaten egg, season with salt, pepper, nutmeg, then add grated Gruyère cheese and place in an earthenware dish buttered and rubbed with garlic. Raymond Blanc’s gratin dauphinois is made by precooking his sliced potatoes in cream and milk, he then adds grated Gruyère into the potato mix before baking, Le Cordon Bleu precooks the potatoes in milk, then adds cream and Gruyère on top of the potatoes before baking, Richard Olney agrees with this method, but does not use cheese. Elizabeth David rejects Montagné’s (and Escoffier’s) use of cheese and eggs and instead cooks the potatoes in their dish with thick cream. The rich creamy potatoes are an indulgence which she regards makes a better use of cream than when it’s poured over peaches.
On the thickness of the potatoes most assume a paper thin slice is the correct dimension, best achieved on a mandolin, however, Richard Olney suggests a thick slice will make neither a less authentic dauphinois nor one that tastes less good. What he does stipulate is the quality of the potato, which should not be mealy. None of these versions include onion in the layers of potatoes, a one-time favourite of mine – which makes a kind of creamy pommes lyonnais, another French classic which marries potatoes and onion.
Whilst wrangling over the name of the dish or the method that makes the best gratin, perhaps we should not worry too much and just enjoy our baked sliced potatoes. As Richard Erlich says in his book, The Perfect… Food Notes and Recipes, even when a potato gratin isn’t perfect, it’s still going to be the best thing you’ve eaten all week.