In a stand mixer, add flour, salt, instant yeast, milk and sugar and then mix at low speed for 8-9 minutes until the dough is soft and smooth.
Cover with a wet cloth and set aside in a warm place until the dough has doubled in size. Press the dough down (to remove most of the air inside) and then divide the dough into two halves.
Then roll one half into a long log and divide into four portions. Flatten one portion and roll it into a circle wrapper.
Scoop around ½ tablespoon to 1 tablespoon sweet red bean paste in the center.Seal the bun completely and then turn it over, making the side with folds facing down. Shape to a round bun. Repeat to finish all.
Cover the buns with a wet cloth, and then set aside for 45 minutes to 1 hour. Pour oil to a pan and place the buns one by one. Fry one side over medium slow fire for 6-8 minutes (with the lid covered) and then turn over the fry for another 4-5 minutes (with the lid removed).