The Mashed Potatoes They Serve in a 3-Star Kitchen

There is mashed potato, and then there is what a restaurant kitchen calls purée. They share a name and almost nothing else. I spent thirty-four years cooking in professional kitchens, and this is the version we made, explained slowly, with the reasons attached. Most of it happens before the pot ever gets hot. You boil the potatoes whole and unpeeled, so the potato cannot drink water, because every ounce of water it takes on is an ounce of butter and hot milk it can no longer hold. You peel them hot, which is easier, not harder. You rice them instead of mashing them, so the cells separate instead of bursting. You use hot milk, never cold, and not much of it. And then there is one more step, the one that stands between very good and three-star, and it needs a tool that costs almost nothing. I will also tell you where to get off the train. The everyday version stops two steps earlier and is still better than what you have been making. The numbers: Potatoes: 3 lb (1.4 kg) yellow potatoes, Yukon Gold or similar, boiled whole and unpeeled. Russets go fluffier and lighter; ratte or fingerling is what the original Paris version used. Salt in the water: about 1 tablespoon per quart, roughly 1 percent. It does very little here because of the skins. Simmer: 30 to 40 minutes at a bare simmer, never a hard boil, until a toothpick meets no resistance. Steam-dry: 1 to 2 minutes in the hot dry pot before ricing. Hot milk: 3/4 cup whole milk per 3 lb of potato, heated, never cold. Cream may replace part of it. Butter, home version: 1/2 lb (2 sticks) per 3 lb of potato, soft or cold cubes, never melted. Butter, restaurant version: 3/4 lb per 3 lb of potato. The famous Paris version ran close to equal weights. Sieve: pass twice through a fine sieve for the three-star texture. A ricer alone is the honest home version. Working temperature: keep the potato above about 150°F. Below that it stops taking fat. Hold: up to 2 hours in a bowl over barely simmering water, or covered in a 300°F oven. Loosen with hot milk, never more butter.