Prepare the Dough: In a large mixing bowl, combine 300g of all-purpose flour, 3g of instant yeast, and 5g of sugar. Gradually add 160g of warm water while stirring until the mixture forms a shaggy dough.

Add Oil and Knead: Add 10g of corn oil to the dough. Knead the dough in the bowl or transfer the dough to a clean work surface and knead for about 8-10 minutes until it becomes smooth and elastic. If the dough feels sticky, dust lightly with flour, but keep it minimal to maintain a soft texture.

Divide the Dough: Shape the dough into a log and divide it into 8 equal portions, each weighing about 60g. Cover with a damp cloth to prevent drying out.

Fill with Red Bean Paste: Take one portion of dough and flatten it into a circle using your hands or a rolling pin. Place 15g of red bean paste in the center, fold the edges over the filling, and pinch to seal tightly. Repeat with the remaining dough and filling.

Shape the Rolls: Place each filled dough ball seam-side down and roll each filled dough ball into an elongated oval shape. Use a knife to score the surface, creating even, parallel lines without cutting too deeply. This step adds texture and a decorative look to the rolls.

Roll and Seal: Roll the dough tightly into a log shape and pinch the ends to seal. Repeat with the remaining pieces.

Rise and Steam: Place each shaped roll on a piece of parchment paper and arrange them in the steamer, ensuring there's enough space between each roll for expansion during steaming. Cover with a damp cloth and let them rise in a warm place for 30-40 minutes or until doubled in size.

Steam the Rolls: Fill a steamer with water and bring it to a boil. Steam over high heat for 15 minutes.

Finish and Serve: After steaming, turn off the heat and let the rolls sit in the steamer for 3 minutes to prevent shrinkage. Carefully remove them and let them cool slightly before serving.