Gather the ingredients.

Spray an 8-ounce microwave-safe mug or cup with nonstick cooking spray. Drop the eggs, milk, and sour cream right into the cup and mix with a fork until blended. Add salt and pepper or any other herbs or spices you'd like to taste. Then stir in the add-ins, if using.

Microwave the egg mixture for 2 minutes for an 800 to a 1000-watt oven (most of them today), 2 1/2 minutes for a 600-watt oven, or 3 minutes for a 400-watt oven. If you like fluffier eggs, remove the mug from the microwave and stir after 1 minute, then return and finish cooking.

You may have to experiment to find the right time for your oven. The omelet should puff up over the top of the cup, then it will retreat somewhat when you take it out of the microwave. The eggs should register 165 F on a food thermometer. (You'll only need to test it once; after that, the time should be the same as long as you keep the ingredient amounts the same.)

Sprinkle with a bit more cheese, let stand for 1 minute, then eat!