Line a heatproof dish with plastic wrap (it doesn't have to be neat).
Pour in the egg mixture, and top with the tomato and torn up cheese.
Microwave for one and a half minutes at 600W.
The egg will start firming up from the edges. If the center is not soft set yet, microwave for a bit more.
Peel the plastic wrap off the plate, and flip the omelette over onto a serving plate. Serve with ketchup to taste.
If you want a more substantial egg dish, try the 2-egg version - Recipe ID: 1485253.
Story Behind this Recipe
And easy microwave recipe! This is a sister recipe to Recipe ID: 1048848 "Two Birds With One Stone: Fluffy Rice Omelette".
Please adjust the cooking time depending on your microwave. Use a plate with some depth rather than a flat one. I used a gratin dish. When you add milk to the egg, it becomes very fluffy, and will rise up like foam in the microwave.