Add instant yeast into the milk. When I first started making mantou, I used 1/2 tablespoon instant yeast as how I was taught. But after making countless times, I realised 1/2 teaspoon is enough. In my earlier videos, you'll see me adding the yeast last but now I learn the trick is to add the yeast into warm milk and sugar mixture first before adding into the mashed sweet potato.
Mash the steamed sweet potato.
Combine milk + sugar + yeast mixture with the mashed sweet potato.
Add flour.
Lastly add oil and knead into a dough.
Close and let it proof for 60 minutes.
White Dough
Dissolve sugar in warm milk.
Add instant yeast into the milk.
Pour the milk mixture into the bowl of flour.
Add oil and knead into a dough.
Cover and let it proof for 60 minutes.
After 60 minutes proofing
Use a rolling pin to roll and flatten the sweet potato dough.
Do the same with the white dough.
Brush water all over the surface of the white dough.
Transfer the sweet potato dough onto the white dough.
Roll the dough and cut into desired size.
Cover with a cloth and let rest for 15 minutes.
Transfer into a steamer and steam for 10 to 15 minutes in medium heat.