Heat the oil in a non-stick omelette pan and fry the mushrooms for 1-2 minutes until lightly browned.
Mix the eggs with the black pepper and pour over the mushrooms. Move the egg from the edges into the centre of the pan to allow any uncooked egg to flood out to the sides. Cook for 2-3 minutes until the egg is cooked.
Add the Philadelphia and fold the omelette in half, the heat will melt the Philadelphia. Serve at once.