Combine 1½ inches of water and vinegar in a wide, small saucepan and bring to a simmer.
Break 1 egg into a small bowl. Once the water is at a simmer, stir the water with the bottom of your slotted spoon clockwise to make a swirling motion in the water. Quickly and carefully slide the egg into the water.
Cover and turn the stove off. Poach until whites are firm and yolks are still runny, 3 minutes and 45 seconds.
Remove the egg using a slotted spoon and drain a bit over the pan.
Place onto a piece of buttered toast, then season with sea salt and freshly cracked pepper, to taste. Serve immediately. Enjoy!