I a large sauce pan, Brown chicken so that it has some color. when Brown add the next 4 ingredients, add wáter and cook slowly until broth is to your taste. Add salt and pepper, (be careful with the salt because the cheese has salt.
Strain the broth and let cool slightly. In another sauce pan sautee very thinly slice onions in butter on low heat until transparent and tender. Take your oven proof consome cups. Fill each one half way with broth add onions and cheese slices. Cover the cups with the puff pastry stick the pastry to the edge of the cup with your fingers. Paint the surface of the pastry with egg wash to that it is shiny when it comes out of the oven.Make a small opening at the top to let off steam. Bake in a preheated oven 350º until Golden Brown.