To prepare the filling mix, finely chop the brussels sprout. In a small, heavy pan, melt ½ Tbsp of butter over low heat. Sauté the brussels sprout in the butter, stirring frequently until it is tender, about 4 minutes. Transfer to a mixing bowl. Add the remaining filling ingredients to the mixing bowl and stir until thoroughly combined. Set aside. Brush the top of each wrapper with the lightly beaten egg. One wrapper will be the bottom of the dumpling and another with be the top. To assemble the dumplings, place 1 tsp of filling about ½ inch from each corner of the bottom wrapper and place another tsp of filling in the center. Each bottom wrapper should have 5 tsp of filling mix spaced equally across the wrapper. Place the top wrapper over the bottom wrappers with the filling mix. Gently press around each mound of filling to seal finger-tight. Using a ravioli maker, cut out each dumpling. (If you don't have a ravioli maker, press around each mound with a small glass to seal, then use a sharp knife to cut out each dumpling. Allow ¼ inch margin around each dumpling.) Set the prepared dumplings aside. In a large pot, heat the chicken stock to boiling. Drop all the dumplings into the broth. Boil 5 minutes. Garnish with chopped green onion and serve immediately. Makes 5 servings as a first course, or 2 as a main course.
