Sprinkle chicken with steak salt. Brown quickly on both sides and cut each breast in half along seam. Saute mushroom onion mix in margarine until tender. Turn heat up and evaporate all liquid. Cool and drain. Thaw puff pastry shell until soft but cold. Put chicken in shell. Top with sauteed mushroom mix, then crab, then 1/2 oz cold Hollandaise. Top with 2nd chicken piece. Pull pastry over filling and pinch closed.
Beat eggs and milk. Brush pastry with it. Bake at 450-475° for 15 mins. Serve with heated Hollandaise and parsley.
Note: This recipe is for one serving only.