Grease a large bowl with cooking oil set aside- we will use it to raise the dough.
Place 3 cups flour, granulated sugar, salt, baking powder, and yeast in the mixing bowl and mix thoroughly using a wire whisk. Set aside.
Place the additional 1/3 cup flour, 1/2 cup water, and 1/3 cup milk in a small saucepan and mix with a spoon or whisk to incorporate, then heat it on a low fire until pasty in texture ( as shown in the photo above). Add it to the flour mixture.
Place the butter in a microwave-safe cup and heat for 1 minute or until the butter is lightly melted and pour into the mixing bowl.
Heat the 2/3 cup of milk in the microwave for 1 minute and add into the mixing bowl. Mix all of the ingredients two to three times using the electric mixer. Add the egg.
Mix the dough using an electric mixer with a hook on. Mix until it will for a fluffy and soft dough. You will notice that the dough is not mixing well, but continue mixing because the dough will become soft and smooth. Transfer the dough to the greased bowl and let the dough rise in a warm place for one hour.