Prepare the Dough:

Combine flour, yeast and sugar in a large bowl. Add water and stir to combine. Knead for a couple of minutes to form a smooth dough. Transfer to an oiled bowl and cover loosely with plastic wrap.

Let rise until doubled, about 2 hours at room temperature. While dough is rising, prepare the filling.

Prepare the Filling:

Combine all ingredients in a medium bowl until incorporated. Taste and adjust seasoning as desired. Cover and refrigerate until dough has risen.

Assemble the Buns:

Line steamer baskets with parchment paper and spray with nonstick spray. 

Bring a pot of water to a gentle boil. 

Once dough has doubled in size, punch it down and shape into a log. Divide into 16 portions and arrange on a baking sheet covered with plastic wrap. 

On a lightly floured surface, roll each dough portion into a circle, leaving the center of the circle thicker than the outer edges. (See video above for reference.)

Add about 2 tablespoons of filling to the center of the dough and gather/pleat the edges, working your way around the circle to close the bun with a twisting motion. Repeat with remaining dough and filling.

Arrange the shaped buns in the prepared steamer basket, leaving about 2 inches between the buns. 

Let buns rest for 10 minutes before steaming.

Steam the Buns:

Gently set the filled steamer baskets above the simmering water and cover. Steam for 15 minutes. 

Serve warm.