In a mixing bowl, add wheat flour, salt, yeast, baking powder, sugar, milk, vanilla essence, and oil.
Mix them well and make into a soft dough. The dough will be initially sticky.
Turn onto a floured surface; knead until smooth and elastic, 8-10 minutes. Place in a greased bowl. Cover and let it rise in a warm place until doubled about 1-1/2 to 2 hours.
Take out the dough and knead one more time. Make the dough into a log shape. Cut the dough into equal size.
Take one dough and make it into a ball shape. Do the same with the remaining doughs.
It is time to fill the stuffing. Flatten the dough using hands and fill it with kaya paste. The recipe for Chocolate Sauce is below the Notes. Cover the stuffing with the dough and make sure there are no openings left.
Arrange the doughs on pieces of baking paper or wax paper and keep them separately. Do the same with the remaining doughs.
Keep them aside to rise for 30- 40 minutes.
Arrange them in a steamer. Now cover the lid with a cloth and tie it on the handle to hold the lid conveniently. Now the dripping water can be absorbed by the cloth the lid is covered with.
Steam the buns for 8-10 minutes.
Serve hot with your favorite hot drink.