Saute half the mushrooms and the chopped onion in butter in a large frying pan. (2) Combine sauteed vegetables with turkey, egg, salt and herbs. (3) Shape turkey mixture into 4 patties. (4) Broil 3-5 minutes on each side until cooked through. (5) While patties are cooking, add remaining mushrooms, wine and pepper to frying pan. (6)Simmer gently and serve sauce over patties.