Sieve bread flour and set aside. Bring butter to room temperature. Preheat an oven to 374℉ (190℃).
Place ingredients [A] in a heat-resistant container and microwave it at 1200W for 30 seconds before combining. (Cooking time depends on the wattage of your microwave.)
Add bread flour, dry yeast, and sugar to athick heat-resistant plastic bag and close it. Combine by shaking.
Add [A] (from instruction 2) to the bag and massage to combine. Once all the dough is mixed, knead the dough in the bag for about 5 minutes while pressing it against the table. If the dough sticks to the bag, peel it off and bring the dough together inside the bag.
Heat water in a pod to 140℉. Place the dough in the bag in the pod with the top of the bag up. Let it sit for 15 to 20 minutes until the dough double in size.
Remove the dough from the bag. Sprinkle some flour on a table and gently press the dough with the palm of your hand.
Roll up the dough tight from top to bottom with both hands and place the rolls seam-side down.
Divide into 8 equal pieces with a scraper or knife. Roll up each piece and place rolls seam-side down.
Place each dough evenly spaced on a baking sheet on a baking tray. Cover with a wet towel and let stand for 10 minutes. Remove the towel and bake in a preheated oven at 374℉(190℃) for 15 minutes.