Put bread flour, sugar, salt and yeast together in a stand mixer attached with a dough hook. Stir to combine then add milk and knead until dough comes together. Add butter to the dough and knead until the dough is soft and shiny. About 6 minutes to 8 minutes.

Weigh the dough. Put aside 500 gms of plain dough in a covered bowl . Let it proof for an hour or until double in size.

Now divide the rest of the dough into two portions. You should roughly have about 250 gms of dough for each portion.

To one portion add the cocoa powder with milk and knead until the cocoa mixes in completely and the dough looks chocolatey in color.

Put in a covered bowl to proof.

To the other portion that's left, add the charcoal and the milk and knead until evenly dark. Put in a covered bowl to proof.

When all the dough has risen, gently knead each of the dough back and then divide each color as follows:-

For chocolate dough, divide into 38gmx2 (large) and 25gmx5 (small) balls...adjust to the final weight of the dough..

For bamboo charcoal dough, divide into 36gmx2 (large) and 23gmx5 (small) balls... adjust to the final weight of the dough...

Plain dough :- divide into balls of 2 balls of 100gm and 5 balls of 55 gms

Chocolate dough :- divide into 2 balls of 38gm and 5 balls of 25gm

Charcoal Dough :- divide into 2 balls of 38 gms and 5 balls of 25 gms

for all the doughs adjust weight of the dough balls as per final weight of the dough.

Using a rolling pin, roll out the cocoa dough balls staring with the large ones. Roll into oval shape. Now roll it like you would a swiss roll. Place under a damp kitchen cloth to ensure it doesn't dry out. Repeat for all the chocolate dough balls.

Next roll the bamboo charcoal dough balls starting with the large ones. Roll into an oval shape, large enough to cover the large cocoa dough roll. Place the coco roll inside the charcoal oval and close the charcoal dough, sealing the chocolate dough inside. Repeat for all the charcoal dough.

Finally use the plain dough balls in the same way, sealing in the charcoal ones inside the plain dough. Now roll into a rope that is twice the size of the loaf pan. Cut into two and then repeat for rest of the dough.

Grease your loaf pan and arrange the dough ropes into the pan. Cover and let it rise for about an hour. Then bake in a pre heated oven at 375* F for 30 minutes. ( 350* F at sea level for 35 minutes)