Remove the skin from the sausage and form into 20 small balls.
Place a ball in the center of each dumpling wrapper, wipe the edges with the beaten egg and seal closed like a half moon.
Pulse the edamame and salt in a food processor until they are broken up into small pieces. Slowly add the truffle oil to form a smooth paste. If it does not come together, add up to 1 tablespoon of olive oil.
Scoop 1 teaspoon of edamame filling into the center of each dumpling wrapper, wipe the edges with the beaten egg and seal closed like a half moon.
Keep the finished dumplings in a single layer on a baking sheet and freeze for 20 minutes.
If you’re not making the soup right away, divide the dumplings into individual serving sizes of 5 in plastic zip bags.
To serve the soup, bring the broth to a boil and cook the dumplings for 3 minutes. Bring the heat down to low and continue to cook until the dumplings are wrinkled in the center. Ladle dumplings and soup into four bowls. Top with shredded cabbage, sesame seeds and a little pepper. If you’d like more salt, add a dash of soy sauce.