Fill a small saucepan with water and bring to a gentle boil. Meanwhile, break the egg into a a small bowl. This will make it easier to slide the egg into the hot water while keeping its shape.
When the water has reached a gentle boil, add the vinegar. The vinegar helps the egg white congeal.
Use a hand whisk to vigorously whisk the water, then slide the egg into the resulting whirlpool. This will help the egg hold its shape when it first enters the water. If making more than one egg, repeat the process (use a larger saucepan).
If some of the egg white spreads out and does not curl itself around the yolk, gently push it in with a spoon.
Cover the pot, turn the heat off and set the timer for 5 minutes.
After 5 minutes, use a slotted spoon to lift the egg out of the water and place it for a few seconds on a paper towel, to drain.
The egg white should be cooked-yet-creamy. The yolk should appear soft. When cut open, it should be thick but gooey. Season with salt and pepper and enjoy!
There is a risk of contracting salmonella when eating undercooked eggs. The CDC recommends cooking eggs until both the whites and the yolks are firm.