1. For the dough , mix the yeast in 1 tbsp sugar with warm water. leave rest until yeast becomes frothy.
2. Mix the rest of the ingredient in a large bowl except oil, add the yeast mixture and knead till combine, then add oil to smoothen the dough. Add a little at a time if the dough is too sticky. Knead well and leave to rise till double.
3. punch down the dough and knead again. divide the dough into few small buns smaller than a tennis ball.
4. Roll each dough by folding few times inwards. Place them on a greased tray apart from each other giving room to rise again.
5. While waiting for the buns to rest , you can make the custard filling by adding the cornflour with evapourated milk and a drop of yellow colour.
6. In a saucepan bring fresh milk and sugar to boil, then stir in the cornflour mixture slowly by stirring constantly until thicken, Off the heat , add the yolk , stir till mix, then add the butter and stir well. Add vanilla. Place custard in a piping bag with small hole nozzle.
7. Pipe custard into the center of the bun, press the custard into the bun.
8. Bake in preheated oven at 250 C for 10 to 15 ins or till golden.