In a mixing bowl, combine the lukewarm water, sugar, and yeast. Mix well until the sugar and yeast are dissolved.

Next, place the flour on the work surface, and create a well in the center. Gradually add the mixture into the well of flour, stirring continuously until a dough begins to form.

Once the dough starts to come together, knead it vigorously for about 10-15 minutes, or until it becomes smooth and elastic. This step is crucial for developing the gluten in the dough, resulting in a soft and stretchy texture.

Divide the dough into 7 equal portions, each weighing approximately 40g.

Cover them with plastic wrap to prevent drying while preparing the red bean paste filling.

Prepare the red bean paste filling by rolling it into small balls, each weighing about 20g.

Take a portion of the dough and flatten it into a small circle.

Place a small ball of red bean paste (about 20g) in the center of the dough circle.

Carefully wrap the dough around the red bean paste, shaping it into a smooth ball with the paste enclosed inside.

Gently roll the dough between your palms to form a smooth, oval-shaped ball, resembling a droplet, similar to the body of a hedgehog.

Using a pair of scissors, make several cuts around the top of the dough ball to create the appearance of "spines." Be sure to cut only halfway through the dough and avoid cutting into the filling.

Use sesame seeds to create eyes for the hedgehog by gently pressing them into the dough.

With the tip of a knife or scissors, cut a small slit to form the mouth of the hedgehog.

Place the shaped hedgehog buns on a steamer lined with parchment paper to prevent sticking.

Cover the buns with a lid and let them rest in a warm, draft-free place for 30-40 minutes, or until they have doubled in size.

Once the buns have risen, steam them over medium heat for about 10 minutes. Begin the steaming process with cold water, and once the water starts boiling, start counting the steaming time.

After steaming, turn off the heat and allow the buns to rest in the steamer for 2 minutes before carefully removing the lid.