Mexican Buns (Roti Boy)

I used this wonderfully soft and fluffy bread recipe from Vinnie Baking Paradise for my Mexican Buns or better known as Roti Boy. 

Overnight Sponge Dough:  Mix well into a dough and leave overnight in the fridge.
215g bread flour
130g fresh milk
2g dried yeast

Bread Dough:
90g bread flour
12g fresh milk
30g egg
7g dried yeast
5g salt
50g sugar
12g milk powder
45g butter (I substitute with cooking oil)

• Knead all the ingredients including the overnight sponge dough (except the oil) into a smooth dough.  Then add in the oil.  Knead until the dough becomes smooth and elastic.  Proof the dough until it doubled in size. 
• Knock out the air in the dough and divide into 10 equal portions.  Shape them into round balls.  Cover and rest for 15 minutes.
• Roll out each dough and add the butter filling.  Seal tightly to prevent filling from leaking out during baking.  
• Place the dough  into individual paper casing and cover.  Proof until doubled in size. 
• Pipe the filling onto the dough before baking in a preheated oven of 185 deg C for about 20 minutes.

Butter Filling: 
100g butter, softened
1/2 tsp vanilla paste
30g caster sugar

•  Beat everything together and chill in the fridge.  Divide into 10 equal portions.

Topping:
50g butter, softened
40g icing sugar
1/2 an egg
1 tsp coffee granules mixed with 1 tsp hot water
50g plain flour

• Beat butter and icing sugar until combine.  Gradually add in beaten egg and coffee.
• Fold in flour.
• Fill a piping bag with the mixture and set aside.