Pau with White Radish Filling/ Sponge Dough Method

I'm using ovenight sponge dough for this recipe. I find that the result is better than normal mixing method. This time I reduce the sponge dough amount from 3 cups flour to 1/2 cup (60g) flour. (Do refer to my last post Smilling char siew pau for steps by steps mixing pictures) 

Ingredients: yield 12 pieces pau
(A) overnight sponge dough
60g plain flour
30-40ml water
1/2 tsp yeast
1 tsp sugar

(B) Pau dough
110ml water
1/4 tsp yeast
1/4 tsp salt
1 tbsp sugar
2 cups plain flour

(C) Filling
1 medium white radish
1 small cucumber (optional)
3 tbsp dried shrimp shells(虾皮‏)
Seasoning (a):1tsp salt, 1tbsp sugar, 1tbsp sesame oil
seasoning (b): salt and pepper (adjust accordingly)

Methods:
~Filling

1. Shred the radish and cucumber. Add in seasoning (a), rest for 45-60 minutes. Squeeze to remove all the liquid. Set aside.
2. Fry the dried shrimp shells with 1 tbsp cold oil till fragrant. Add into white radish mixture together with seasoning (b).

~Sponge Dough
Mix all till form a dough. Immediately store in greased plastic bag (no proving needed). Make a tight knob without leaving any space for the dough. Store in fridge at least 4 hours. It can be kept up to 7 days. Thaw it for 10-15 minutes at room temperature before use. You can prepare the sponge dough one night before. Tear into small pieces before use.

~Pau Dough
1. Put all ingredients from (B) except flour into a pan. Stir to mix. Follow by pieces of overnight sponge dough.
2. Add in the flour and knead into a smooth dough. Cover and rest for 10 minutes.

3. Transfer to working surface. Divide the dough into 12 portions and mould into balls. Flatten balls into round shape. Wrap in filling and place on lined paper(I used banana leaf). Rest the pau in steamer for 15 minutes. I used to place a cloth around the steamer. This is to prevent pau from getting wet at the base during the steaming process.
4. Bring the water to boil. Steam with medium low heat for 10 minutes. Once the steaming time is over, off the heat, leave the pau inside the steamer for 1 minute before open the lid.