Heat butter in a non stick pan, and spread over surface of the pan with a pastry brush. Add eggs, cover and let cook over medium heat, until set.
Meanwhile heat cream cheese in the microwave until soft and spreadable. Rinse and drain capers and finely dice onion.
When eggs are set, slide them from the pan onto a plate. Spread cream cheese, sprinkle with capers and onion and cover with lox. Serve with lemon slices.