The secret method of making buns

Yeast recipe:
500 grams flour
300 g warm water
5 grams yeast
5g baking powder
10 sugar (can not be put in summer)
Minced Meat Recipe:
1000 grams minced meat
300 g green onions
35 grams ginger
Add 7 grams of salt per 500 grams of minced meat, including the weight of all ingredients (if the broth is added without salt, the weight should also be included)
Other seasonings are appropriate according to personal taste