Crack an egg into a small mesh strainer set over a bowl. Let the runnier/watery parts of the whites run off through the strainer into the bowl.
Place the egg into a separate bowl.
Set a large pot of water on the stove and heat it until it’s at a light rolling boil (not vigorous). Add some apple cider vinegar to the water.
Using a spoon, stir the water slowly in a circular motion to create a vortex in the middle.
Carefully drop the egg into the vortex and cook for 7 minutes, or until whites are cooked and yolk is still soft/runny.
Remove egg with a slotted spoon and place on a paper towel lined plate until ready to use.