Tausa (red bean) Filling Steamed Bun

Ingredients
Basic dough buns:
250 g low protein flour
Instant yeast 10 gr
150 cc water

Main dough buns:
90 g low protein flour
60 gr tang mien flour (can be replaced with low protein flour)
70 gr powdered sugar
1 tablespoon baking powder
¼ teaspoon baking ammonia** (may not be used)
3 tablespoons water
50 grams of white butter

Directions:
Mix all the ingredients for the basic dough ingredients then knead until no longer sticky to the hand (approximately 10 minutes).
Cover with a damp cloth and allow the dough for about 1 hour until fluffy 2 times. While waiting, make the filling*. Mix all the main dough ingredients into the basic dough then knead until smooth and no longer sticky.
Weigh the dough for 20-25gr each. Roll each piece flat, put filling in center and seal shut then steam for about 15minutes.

*Tausa Filling (sweet flavor) recipe
For a sweet filling / Tausa:
- 150 grams of red beans
- 75 g of cooking oil
- 100 gr sugar
Directions:
- Soak beans for 3 hours. Cook the beans until
ripe and soft. Remove and puree in blender.
- Heat 3 tablespoons of cooking oil in non-stick frying pan.
Put the beans finely and stir, add the sugar and
alternately oil, little by little while stirring it until dry.

** what is baking ammonia?