1. In a bowl, combine the meat, chicken broth, oil, soy sauce, scallions, cornstarch, salt, sugar, and chestnuts. Work a fork through the mixture to make sure it is well mixed. If it’s too dry, add a little water or soy sauce.
2. Put a teaspoon of filling in the corner of a wonton skin. Wet the edges of the skin with egg wash, and fold one edge over to the opposite (diagonal) edge to form a triangle. Press the corners together and use the egg wash to stick them to each other.
3. Cook the wontons in the soup for about 10 minutes, until the filling is cooked. Don’t overcook, because they may fall apart.
4. Before serving, garnish with any combination of chopped scallions, shitake mushrooms, thinly sliced pastrami, or thin noodles.