Fill a microwave-safe mug or bowl with 1/2 cup water
Add 1/4 teaspoon vinegar if desired
Crack one egg into the water
Pierce the yolk gently with a toothpick or knife tip
Cover the mug or bowl with a microwave-safe plate or lid
Microwave on high for 45 to 60 seconds
Check the egg; microwave in 10-second intervals if needed
Remove the egg with a slotted spoon
Drain on paper towel
Season and serve