In a bowl, combine 100 grams of brown sugar with 230 grams of hot water. Stir until the brown sugar is completely melted.

Allow the brown sugar water to cool to a temperature between 90°F to 110°F (32°C to 43°C), then add 5 grams of high-sugar-tolerant yeast. It's crucial to use yeast that can withstand high sugar content to ensure proper fermentation.

Gradually add 500 grams of all-purpose flour to the yeast mixture, stirring until a dough forms.

Knead the dough until it becomes smooth and elastic. This will help develop the gluten and create a light and fluffy mantou.

Seal the dough in a bowl and let it rise until it doubles in size. A well-risen dough will have many air bubbles, indicating that the yeast is active.

Once the dough has risen, knead it again to release any air bubbles.

Roll the dough into thin sheets and spread a layer of brown sugar evenly over the surface.

Dampen one edge of the dough with a little water to help seal the mantou.

Roll the dough into a log and then into a long strip, making sure to pinch the opening tightly to prevent the filling from escaping during steaming.

Use your hands to tear the dough apart, creating a rough surface. Avoid using a knife to cut, as this will prevent the formation of the rough surface. Each time you tear the dough apart to shape a mantou, pinch the next one, making them individually.

Sprinkle some granulated brown sugar on top of the mantou for an extra touch of sweetness.

Place each mantou on parchment paper and let them rest for about 8 minutes while you bring the water in the steamer to a boil. When placing the mantou in the steamer, ensure that the rough surface is facing upwards. This is crucial for ensuring that the mantou blooms beautifully during steaming.

Once the water is boiling, steam the mantou over high heat for 15 minutes.

After 15 minutes, turn off the heat and allow the mantou to rest for 3 minutes before opening the lid to check.