In a medium bowl, combine all the ingredients for the wontons (except for the wrappers and milk) and mix with your hands or large spoon until well combined.
Lay 6 to 12 wonton wrappers on a work surface and place about half a teaspoon of stuffing right in the center of each wrapper. Brush the edges with a little bit of milk and then fold the wrappers in half, either vertically or diagonally (see pictures in post for visual reference). Press to seal, taking care to remove as much air as you can and then “crimp” the top edge slightly between your fingers.
Brush a little bit more milk on the "corners" of the folded wontons and then bring those corners together, pressing lightly to ensure that they stick well.
Repeat with the rest of the wonton wrappers until you run out of stuffing.
Be sure to keep the wrappers and finished wontons covered with a damp cloth while you are working to avoid them drying out.
When all the wontons are done, you can either cook them immediately or refrigerate or freeze them in airtight containers to cook at a later time; just arrange them in a single layer on a baking sheet lined with parchment paper and make certain that they do not touch until completely refrigerated or frozen to prevent them from sticking together. Refrigerated wontons will keep for maximum of 24 hours, while the frozen ones will keep for up to several months. You can cook the frozen wontons directly from the freezer without thawing them first.
To make the broth
Combine the chicken stock, water, sesame oil, honey, rice vinegar, garlic, and ginger in a stock pot. Pound the lemongrass with a meat mallet or blunt object until well bruised and add it to the stock. Bring to the boil and then lower the heat to a slow simmer. Cover loosely and simmer for 10 minutes, then fish out the ginger, garlic and lemon grass and bring back to a roaring boil.
To cook the wontons
Delicately add the wontons to the broth, about 5-6 per person, and boil until fully cooked, about 2 to 3 minutes for fresh wontons, 6 to 8 minutes for frozen.
Ladle into bowls and garnish with chopped green onions.
Alternatively, you could also cook the wontons in plenty of salted boiling water then drain them, put them directly in the bowls and ladle the warm broth over the cooked noodles.