Step by step

Cut the vegetables into small cubes and cook in a saucepan with a little olive oil

Tips
Take care that the vegetables are not too warm before adding the egg, as this might result in overcooking them and an outcome rather like scrambled eggs.
Trivia
Egg yolk is rich in protein and 'good' fats, i.e. the monounsaturated and polyunsaturated ones. So, a panacea for health!