Saute the onion in 2 tablespoons of butter until soft and mix thoroughly with the minced meat, breadcrumbs, milk, salt, pepper, parsley and egg. Shape mixture into balls 1 inch in diameter. In a large frying pan saute the meatballs in butter or oil until they have turned brown on all sides. Pour the wine over the meatballs and heat for a few minutes.
Serve hot. Makes about 3 dozen meatballs for appetizers.