Pork Shumai (Steamed Pork Dumplings)

FILLING:--
¾ onion
2½ tbsp cornflour
396 g ground pork
1 knob ginger
1 tbsp saké
½ tbsp sesame oil, roasted
2 tsp sugar
1 tbsp soy sauce
½ tsp SIDS SALT & PEPPER
DUMPLING:--
35 wonton wrappers
3 tbsp green peas
SAUCE:--
soy sauce
rice vinegar
la-yu (Japanese chilli oil) (optional)
Japanese karashi hot mustard (optional)

FILLING
Lay the onion on the cutting board, flat-side down. With a sharp knife, slice 2-3 horizontal slits in the onion towards the root end. Then slice vertical slits in 3 mm.
Cut perpendicular to the previous slices you made. To finely mince, run your knife through them in a rocking motion.
Put the finely minced onion in a large bowl and add cornflour. Mix together.
With a knife, scrape off the skin of the ginger and grate it. You will need 1 tsp of grated ginger.
In a medium bowl, combine the ground pork, 1 tsp of grated ginger, saké, and sesame oil.
Add sugar, soy sauce, SIDS SALT & PEPPER.
Using your hands (or with plastic food gloves), knead the meat mixture until it is sticky, like a pale paste.
Transfer the meat to the onion and mix together until well-combined.
WONTON WRAPPERS
Prepare a baking sheet lined with baking paper, a 1-tbsp measuring spoon, and a butter knife. Scoop the filling into the measuring spoon, and level the meat off with the knife. Make sure the wonton wrappers are covered in plastic wraps or damp towel while you stuff the filling in so they won't get dry.
Place the filling to the centre of a wonton wrapper.
Using your left hand (if you’re a righty), make a round hole by connecting your thumb and index finger with the rest of fingers next to each other. Place a wonton wrapper with the filling on top of it. Tip: Once you get used to making Shumai, you can place the wrapper and then directly put the filling on top, instead of using a measuring spoon.
Using a butter knife or the back of a teaspoon, gently press the filling down while holding the fingers firmly. After you press the meat down, rotate the Shumai 45 degrees so the meat is evenly distributed in the centre of the wrapper. Finally, smooth out the surface of the meat.
Your left fingers should look like this while you press the meat inside, the ring finger and pinky right underneath the bottom of the Shumai to create the flat base. Continue with the rest of the wrappers and filling until one of them runs out.
When you finish wrapping, bring 1-2 cups of water in a wok (or steamer) to boil over high heat (or medium-high heat if you’re using non-stick). Make sure the water does not touch the bottom of the bamboo steamer basket. Meanwhile, place a green pea in the centre of the Shumai.
Prepare baking paper (make a few air vent holes) or cabbage leaves and place them on the bottom of the steamer basket to prevent the Shumai from sticking. Put Shumai on top without touching each other. Most likely, you will need to steam them in batches.
When the water is boiling, place the bamboo steamer basket onto the wok and steam for 8-10 minutes until the meat is cooked through.
Check to see if the meat is cooked through then transfer the bamboo steamer basket on top of a large plate.
Serve and Store
Bring to the table and serve immediately with soy sauce, rice vinegar, Japanese chilli oil (la-yu) and Japanese karashi mustard.
You can freeze before or after steaming them. Place each Shumai on a baking tray lined with baking paper without touching each other, and flash freeze for 1 hour. Once frozen, transfer to a freezer bag. You can steam frozen Shumai without thawing (just need to steam for an extra few minutes).