Fill a microwave-safe mug or bowl with 1/2 cup water
Add 1 teaspoon vinegar, if desired
Crack one egg into the water
Pierce the yolk gently with a toothpick or fork
Cover the mug or bowl with a microwave-safe plate or lid
Microwave on high for 45 to 60 seconds
Check the egg and microwave in 10-second intervals until the white is set
Remove the egg with a slotted spoon
Drain on a paper towel
Season and serve immediately