Place onion and ginger unpeeled on a baking sheet under a broiler. Broil for 10 minutes. Peel off the skin and place the onion and ginger on a piece of cheese cloth. Add the black cardamom, star anise, cinnamon stick, peppercorns, fennel seeds, and coriander seeds. Wrap the cloth into a bundle and secure it with some butcher's twine.

Place broth, spice bundle, soy sauce, sugar and fish sauce in a small saucepan over high heat. Bring the broth to a boil, then reduce to a simmer. Leave the broth to simmer for 1 hour or until reduced by half.

Bloom gelatine sheets in cold water until soft. Wring out the sheets to removed excess moisture and add them to the broth. Remove the broth from the heat and stir until the gelatine dissolves.

Pour the broth into a hotel pan or a casserole dish and refrigerate for 1 hour or until set.

Place flour and salt in a large mixing bowl, whisk to combine. Add hot but not boiling water to the flour mixture and stir until a shaggy dough forms. Turn the dough onto a well-floured surface and knead until smooth and silky. This should take some time. Don't be discouraged if your dough is lumpy, just keep kneading.

Return the dough to the bowl and cover with plastic wrap. Let the dough rest for an hour before using.

Place all filling ingredients in a large mixing bowl and stir using chopsticks, so you don't over-mix. A light film will form on the side of the bowl when the meat mixture is mixed enough. Refrigerate until ready to use.

Roll your dumpling skin dough into an 18-inch snake. Cut the snake into 18 1-inch pieces. Form each piece into a circle-shape using your fingers. With a well-floured rolling pin or better yet a dumpling dowel, roll each piece into a circle about 4-inches in diameter. It should be slightly see-through. Make sure the edges are particularly feathery.

Take the soup base out of the refrigerator and cut it into cubes using cross-hatch motion. Add the cubes to the filling and stir lightly until just combined.

Place 1 tablespoon of the finished filling into the centre of a dumpling skin and pleat in a circular motion until sealed. Repeat until all of the skins are filled.

Place finished dumplings in a bamboo steamer lined with napa cabbage leaves or parchment steamer liners. Fit the steamer in a wok with 3-inches of boiling water. Steam dumplings for 8 minutes. Serve finished dumplings with black vinegar, chilli oil and soy sauce.