In a mixing bowl, combine the flour, sugar, yeast, baking powder, and salt.

Pour in the warm water and vegetable oil.

Turn the mixture out onto a floured surface and knead for about 5-7 minutes until smooth.

Place the dough in a greased bowl, cover with a kitchen towel, and let it rise in a warm place for about 30 minutes.

Once risen, punch down the dough and divide it into 12 equal pieces, shaping each into a ball.

Flatten each ball if desired and place filling in the center, then gather the edges and pinch to seal.

Place the buns on parchment paper squares to prevent sticking and arrange them in a steamer basket.

Bring water to a boil and steam buns for about 15 minutes.