Put the ground pork in a bowl, add the beaten egg, put in the chopped onions, then add the salt and pepper. Place 1 wonton wrapper on a work surface with one point facing you. Mound 1 teaspoon filling in bottom corner. fold bottom corner over filling. Bring side corners together, overlapping slightly. Pinch together firmly to seal. Cover finished wontons. (Cook immediately,or refrigerate up to 8 hrs. or freeze in resealable plastic bag.)Bring the chicken stock or beef stock into a boil. When boiling drop the wontons into the boiling stock, and cook until the filling is no longer pink. Serve hot, and garnish it with sliced onions.