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 very fresh cold large egg into a custard cup or small ramekin. Use the handle of a spatula or spoon to quickly stir the water in one direction until it's all smoothly spinning around.
TIP: Use this whirlpool method when poaching a single serving (one or two eggs). For bigger batches, heat the water, salt and vinegar in a 12-inch nonstick skillet and do not stir.
Add the egg: 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.
Let it poach: 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.
Photograph by David Malosh