Heat the water: Add enough water to come 1 inch up the side of a narrow, deep 2-quart saucier. Add 1 teaspoon kosher salt and 2 teaspoons white vinegar and bring to a simmer over medium heat. Meanwhile, crack 1 egg into a custard cup or small ramekin. Quickly stir the water in one direction until it's all smoothly spinning around.
Swirl and drop: Carefully drop the egg into the center of the whirlpool. The swirling water will help prevent the white from "feathering," or spreading out in the pan. This may only work with 1-2 eggs, whirlpooling the third or more may risk scrambling.
Poach 5 min: Turn off the heat, cover the pan and set your timer for 5 minutes. Don't peek, poke, stir or accost the egg in any way.
Lift it out: Remove the egg with a slotted spoon and serve immediately. Alternatively, move the egg to an ice bath and refrigerate up to 8 hours. Reheat in warm water just before serving.
