On this side of the Atlantic whipped potatoes are prepared by boiling anonymous potatoes in water until they are soft. Using the easiest method at hand, the potatoes are then whipped. Additions of an idiosyncratic amount of hot milk and a whimsical wedge of butter are made while tending to other tasks in the kitchen. When everything is mixed you are done. Serve.
The French, however, begin with a history lesson: One first contemplates the contrasting meanings of "La Puree de Pommes de Terre" for the peasant class vs. the aristocracy. In the kitchens of the poor "La Puree" was a simple dish enriched by the restrained use of precious butter and milk. But for the rich "La Puree" was a chance to show off food bling. The liberal use of butter and refined cooking techniques elevated grandmother's sturdy potato dish into the realm of a light, ethereal essence.
Thus the process of making whipped potatoes in France begins with a philosophic question: are you a simple, close-to-the-earth peasant or are you a person of refined tastes and ample means? There is no morally correct answer to this question but culinary hell awaits those who try and straddle it.
La Ratte potatoes enter this story as the darling, potato-of-choice in the "La Puree Pomme de Robuchon” recipe by a modern and famous French chef, Joel Robuchon. The dish can be described as the union of potato and butter in the body of a light but luxuriant sauce. It has inspired as many “wows” from critics as it has professional chefs to re-create the dish in their own restaurants. On its surface the dish is seductively simple yet it is technically challenging to execute perfectly. Despite several published versions of “tell-all” Robuchon recipes both the ingredients and the process remain uncertain and slightly mysterious. In regards to the potatoes most sources and Robuchon himself cite La Ratte fingerlings as “the potato.” To gardeners, however, this seems an odd choice given that La Ratte is a waxy spud that is prone to becoming gummy in a puree. But Robuchon acolytes defend his choice of potato claiming it to be his version of a culinary handicap that showcases his superlative technique. His critiques respond by hinting that he may actually use a floury potato, BF15, which is common in France. They claim the La Ratte suggestion is a smoke screen intended to sabotage his competition. You may choose to believe it or not but these kinds of debates fill culinary blogs and keep some people up at night.
Whether you are tempted to scale the heights of Robuchon’s whipped potatoes or not La Ratte remains a fine potato with a long history. Its genetics suggest that is a ‘New World” potato that came out of 18th century European crosses. Legend more than record suggests it was grown in France for a long time before being lost in the late 1800s. It was re-introduced to France from the Alps in the early 1900s and has been a small-scale agricultural item since that time. At present its grown primarily around Burgundy but its recent fame has encouraged larger production outside the region.
In the United States La Rattes have captured the imagination of several high-end chefs, including Thomas Keller and Charlie Trotter. Commercially a selection of La Ratte called “Princess La Ratte” is making the rounds but its distributor hasn’t offered evidence of its genetic provenance or of its improvements over open pollinated stock.
My experience with La Ratte is only a few seasons deep but I have grown both open stock and the “Princess” selection. I have also attempted Robuchon’s whipped potatoes several times. I don’t have the training of a French chef nor do I own a proper tamis but I ate the results with relish. If anyone wants my recipe I will sell you a few La Ratte potatoes plus vague and slightly mysterious instructions about growing them. I might be different than the French but I can learn.