Microwave on medium power for approximately 1 minute and 30 seconds. Keep your eye on the bowl as oatmeal has a tend to boil over in the microwave.
Remove from microwave and stir in the peanut butter and stevia until well-blended. Stir in the egg whites until well-blended.
Microwave on medium power for 1 minute.
Remove and check the consistency. Eggs should be smooth, not scrambled or watery. If you would like it cooked a little more, microwave in 10-second increments on high, checking each time for consistency. Don't cook it too much or it will get curdled.