In a bowl of a stand mixer, add flour, corn flour, sugar, yeast, baking powder and salt. Mix well.
Combine oil and water. The water should be little hotter than lukewarm, but not boiling hot.
Use a stand mixer with a hook attachment to knead the dough. (If it is not available, you can use your hands to knead it)
Pour water and oil mixture into the flour mixture gradually kneading on medium high speed. Knead well for about 10 minutes using stand mixer or for 5 minutes using hand. The dough should be smooth and soft to touch. Knead a little more from your counter top.
Keep it in a greased bowl, cover it and let it rise for 60-90 minutes in a warm place until doubled in size.
Punch down the dough to release the air bubbles and knead for five minutes.
Roll out the dough in 1 cm thickness. Spread a little bit of oil on the surface of the dough so that the buns don't stick to each other.
Using a 3 inch cookie cutter, cut out the dough into small circles. You can roll it further if it is very thick.
Keep these dough circles on a cupcake liner or small pieces of baking sheets. Fold the dough in half and roll it gently.
Keep it cover with a tea towel and let it rise again for 1/2 an hour.
Fill the steamer with water and keep it on the stove. Once it comes to a oil, reduce heat to medium low and place the buns in it and steam for 10-12 minutes until it turns puffy and soft and cooked all way through. (By this time make the Korean chicken)