It's surprising but true: Joel Robuchon won his Michelin stars with, of all things, mashed potatoes. When he first prepared his soon-to-be signature dish at Jamin in Paris in the early 1980's, he stunned a world that was only familiar with grandma's satisfying but ordinary mashed spuds. Since then, Robuchon's incredibly rich potato purée has become so popular that customers demand it at every one of his restaurants. The key to the dish is to keep the potatoes hot as you mix in so much chilled butter—a pound for every two pounds of potato—that it takes vigorous and constant stirring to keep them smooth and silky.
- 2 lb. yellow-fleshed potatoes, such as yukon gold, unpeeled
- Kosher salt, to taste
- 1⁄4 cup milk
- 1 lb. unsalted butter, cubed and chilled