Crack the eggs into a bowl and beat.
Slice the mushrooms and place in a heated non stick frying pan with the oil. Fry on a medium heat until mushroom water has evaporated.
Add in the egg mixture, stirring with a wooden spoon for 30 seconds and leave to cook for a further 2 minutes. Then turn over the omelette and cook for a further 2 minutes. Check the egg has solidified before eating.
Turn out omelette onto your serving plate, grate on some black pepper and start eating.