Joel Robuchon style potatoes are often said to be the best in the world by top chefs. Robuchon was one of the great chefs, a highly decorated French chef who was named ‘Chef of the Century’ by guide Gault Millau in 1989.
Robuchon potatoes are cooked in lightly salted water with skins on and then drained. the potatoes are then peeled and passed through a food mill .. dried out over a low flame and then emulsified with butter and milk. And, then to achieve that velvety texture, the potatoes are passed several times through a fine drum sieve.
Adapted from from L'Atelier of Joël Robuchon and Chef Steve Benjamin of L'Atelier de Joël Robuchon (MGM Grand) - Las Vegas, NV
500 grams Ratte potatoes (fingerlings or Yukon's can also be used)
250 grams chilled unsalted high quality French butter-- chilled and cut into small pieces
Hot Milk, as needed 1/2 -3/4 cup
salt to taste
NOTES ON BUTTER QUANTITY:
The classic Robuchon mashed potatoes, as is served at the L'Atelier de Joël Robuchon uses a ratio of potatoes:butter = 2:1. However in Robuchon's book written by Patricia Wells which was targeted for American audiences, the ratio is given as 4:1.
If you go with the 2:1 ratio, don't plan on large portions. Just a few table spoons will satisfy most. The image above used a ratio of 4:1
Scrub the potatoes (shown to left are Ratte's from Union Square Market) Do not peel the potatoes. Cook them in their skins covered by at least 1 inch of water. For each liter of water add 10 grams of salt. Simmer uncovered over moderate heat for 20-30 minutes or until a knife can easily be inserted and removed. As soon as the potatoes are done remove and drain. Do not allow them to sit in the water. Meanwhile, bring the milk just to a boil in a medium sized saucepan and set aside.
Discard the skin after it has been peeled away. Place the pan over low heat and using a wooden spatula stir the potatoes to dry them out (approximately 4-5 minutes).
Begin adding 3/4 of the butter, little by little vigorously stirring until the butter is incorporated. This should be done in a similar manner as one prepares any butter emulsion (starting off with a very small amount of butter to start the emulsion).
Then stir the puree with a whisk to incorporate air and make the puree fluffy.
Taste for seasoning. If not using immediately, place in the top of a double boiler over simmering water. Whisk occasionally to keep smooth. The puree can be further adjusted with hot milk or butter before serving.
Remember because they are so rich you only need a small amount per person.
Note: Robuchon will sometimes use olive oil or goose fat for some of the butter, and nutmeg or saffron as seasonings.