Combine the flour, sugar, salt, and baking powder.
Add the water, milk, and oil, and mix together to make a dough. Wrap in plastic wrap and let rest for 30 minutes.
Mince the Japanese leek and shiitake mushrooms, finely dice the bamboo shoot, and combine all of the filling ingredients and mix until it has a paste-like consistency.
Divide the dough into eight equal portions, then roll them into balls. Roll each ball flat with a rolling pin into a 10-13 cm diameter circle.
Place a portion of the filling on top, then pull the dough over the filling from the edges to meet at the top.
Line a frying pan with parchment paper, pour in some water, place the buns on top of the paper, then steam over low-medium heat for about 10 minutes.
Story Behind this Recipe
My child was watching a kid's TV program that showed how to make 'nikuman' (steamed pork buns), and so wanted to eat some. So, I tried it out. Using the ingredients and steaming process as a reference, I adjusted the amount of ingredients to create my own variation.
If you are carefully in measuring the amounts, these will turn out just like the delicious store-bought steamed pork buns!