Prepare a cutting board by covering it with a thin layer of flour in order to prevent the dough from sticking.
Then, take the fermented dough from the bowl and put onto the cutting board.
Roll while removing gas then cut into 4 pieces. Each piece should be 40-45g.
Make each piece round and cover with a wet towel to avoid dryness.
Use rolling pin and make each rolled dough into a thin round wrapper. The diameter should be 5 inches(12.7 cm) big.
Put the filling in the center of the dough.
Pick up two sides of the dough and pinch together. Then pick up another two sides and pinch together again. Then use two fingers, index finger and thumb, to roll tight to seal. Do all the same way.
Add parchment paper in the steamer and add the Nikumans on top of that. Ferment for 15 minutes.
Meanwhile, boil water in a pan or pot that is the same size as the steamer. (I use a pan)
After boiling the water, put steamer on top of the pan(or pot), and turn the heat to medium. Cook for 12-14 minutes.