Cocoa Bo Lo Bao (sweet buns)

This is one of my three varieties of Bo Lo Bao that I have done so far,

Recipe from Gourmet living magazine
Ingredients
1 1/2 tsp instant yeast
240g milk
50g castor sugar
360g bread flour
90g plain flour
1 tsp salt
1 egg yolk
10g milk powder
60g salted butter, softened to room temperature
1 tsp + 1/8 tsp cocoa powder

Methods
Knead ingredients ( except the butter) into a rough dough. Add butter and continue to knead until dough is smooth and glossy.
Cover and let it rise for an hour or, until it double it's size.
Punch down air and roll dough into a ball.  Cover and let it rest for 10 minutes.
Divide into 12 equal portions, roll into balls. Lay them on baking tray with parchment paper.
Cover and let it rise for about 45 minutes or, until it double it's size.

Crust ingredients
60g salted butte
50g icing sugar
100g plain flour
1/4 tsp salt
2 egg yolks
1 tablespoon milk powder
1 tsp + 1/8 tsp cocoa powder

Method
Soften butter at room temperature. Add icing sugar to beat until light colour. Add remaining ingredients and mix well.
Divide into 12 portions and roll to flatten.

For brushing
some egg wash

Assembly
Place flattened dough on the bread. Use spatula to press out lines.
Brush with egg wash.
Bake in preheated oven at 180C for about 15 to 20 minutes till cooked.

flatten the cocoa dough

use a spatula to  press out the lines