1) Clean and devein the shrimp. Clean the pork.
2) Mix the pork with all the marinade ingredients. Cover and put in the fridge for an hour.
3) Mix the shrimp with 1/2 teaspoon salt. Cover and put in the fridge for an hour.
4) Remove the pork and shrimp from the marinade and clean.
5) Chop the pork and shrimp together until well mixed.
6) Add ginger, peas, mushrooms and onion. Mix well.
7) Work with one siu mai at a time. Take a wonton wrapper and place about 1 teaspoon of filling in the middle. Wrap. Repeat till all the dumplings are done.
8) Prepare a bamboo steamer with some parchment paper or foil.
9) Place the wrapped dumplings on top and steam over high heat for about 10-15 minutes.
10) Serve hot. These will be perfect with some sweet chilli sauce.