If making mandu from scratch, mix the pork, tofu, bean sprouts, chives, garlic, soy sauce, sesame oil and egg in a bowl until it holds together in one mass.

Place a spoonful of filling in the center of each wrapper, wet the edge with water, fold in half and pinch the seam shut, then bring the two bottom corners together and press to seal, like tortellini.

Brown the beef in a dry pot over medium heat 2 to 3 minutes, add the water, and bring to a boil.

Skim the foam, then simmer 15 minutes to build the broth.

Add the garlic and bring the broth back to a full rolling boil before adding the mandu — a gentle simmer lets the wrappers go soft and split before the filling inside is cooked through.

Cook the mandu 5 to 7 minutes if fresh, 8 to 10 minutes if frozen straight from the freezer, until they float and the wrappers look slightly translucent.

If using the egg, drizzle it in a thin stream over the surface in the last 30 seconds and let it set into ribbons without stirring hard.

Season with soy sauce, salt and pepper, ladle into bowls, and scatter with scallions.