Mix the Ingredients: In a large mixing bowl, combine the flour, black sesame powder, and yeast. Slowly add the warm water while stirring continuously. Stir until the mixture forms loose, shaggy dough clumps.

Incorporate the Lard:Once the dough has started to come together, add the lard (or substitute with vegetable oil). Continue kneading the dough until the lard is fully absorbed, and the dough becomes smooth and elastic.

Rest the Dough: Cover the dough with a damp cloth or plastic wrap and let it rest for 5-6 minutes to relax the gluten. This step will make it easier to roll out later.

Make the Filling: In a separate bowl, mix the black sesame powder and sugar. Gradually add water, 1 tablespoon at a time, until the mixture forms a smooth, spreadable paste. You want a consistency that is neither too runny nor too thick.

Set the black sesame paste aside while you prepare the dough.

Roll Out the Dough: After the dough has rested, roll it out into a large rectangular sheet on a lightly floured surface. The thickness should be about 5-7 mm (¼ inch). Be careful not to roll it too thin, as you want a good balance of dough and filling.

Spread the Filling: Evenly spread the black sesame filling across the entire surface of the dough, leaving a small border around the edges. Use a spatula or the back of a spoon to ensure the filling is distributed evenly.

Roll Up the Dough: Starting from one of the longer edges, carefully roll the dough into a tight log, similar to rolling up a jelly roll or cinnamon roll. Once rolled, pinch the seam tightly closed to seal the dough. Then, gently roll and shape the dough to form a more rounded log. Take your time to ensure that the roll is even and the filling stays inside.

Cut the Rolls: Once the dough is rolled, use a piece of thread or dental floss (this prevents squashing the roll) to cut the log into individual rolls, about 4-5 cm (1.5-2 inches) thick. To do this, slide the thread under the roll, cross the ends over the top, and pull to slice cleanly through the dough.

Let the Rolls Rise: Arrange each cut roll on a piece of parchment paper. Then, place the parchment-lined rolls in the steamer, ensuring there is enough space between them to allow for expansion.

Cover the steamer with the lid. Let the rolls rise for about 45 minutes, or until they have doubled in size.

Steam the Rolls: Once the rolls have risen, bring water to a boil in a steamer pot. Place the mantou rolls in the steamer. Cover the lid and steam over medium heat for 15 minutes.

Rest After Steaming: After steaming, turn off the heat but leave the rolls in the steamer for an additional 3 minutes with the lid still on. This resting period helps prevent the mantou from collapsing due to a sudden change in temperature.