In a large bowl, combine all the dry dough ingredients (flour, sugar, yeast, lard) and mix well to remove any clumps.

Gradually pour in the warm water while stirring with chopsticks until a coarse, sticky dough forms with no dry flour left.

Using your hands, mix until a shaggy dough forms and no dry flour remains.

Turn the dough out onto a clean, un-floured work surface.

Begin kneading. The dough will be sticky at first. Use the heel of your hand to push the dough away from you, then fold it back over itself. Continue this motion.

Knead vigorously for a full 12-15 minutes. This is the key to developing gluten for a smooth, elastic dough. It's ready when it becomes very smooth, supple, and no longer sticks to your hands or the counter.

Divide the dough into 2 portions.

Take one portion and roll it into a strip.

Flatten slightly with your palm and lightly roll with a rolling pin to about 5 cm wide, keeping the center slightly thicker and edges thinner.

Roll the red bean paste into a strip the same length as the dough.

Place one bean paste rope down the center of the flattened dough strip.

Bring the edges of the dough up and over the filling, pinching them together tightly to seal completely. You should now have a long, filled log.

Flip the roll seam-side down.

Gently roll this sealed log back and forth on the counter to even it out and create a smooth, uniform cylinder. Repeat the entire process with the second piece of dough and bean paste filling.

Using a scraper, cut into approximately 20 mini buns.

Line a steamer with a steaming cloth or parchment paper. Place the buns with about 2 cm spacing to prevent sticking. Cover and let proof over warm water until the dough volume increases by 1.5× and springs back lightly when pressed.

Fill a steamer with enough cold water. Place proofed buns inside. Bring to a boil over high heat, then reduce to medium and steam for 13 minutes. Start timing once the water boils to ensure buns are fully cooked.

Turn off the heat but keep the lid on. Let the buns rest in residual heat for 3 minutes to ensure they stay soft and fluffy.

Carefully remove the lid and transfer buns to a plate. Let cool for 1 minute before serving. Freshly steamed buns are soft, sweet, and tender; they maintain their texture even after cooling.