Moo-Cow Pattern Milk Bread

1. The night before, prepare the roux by mixing flour and water. Wrap it in a cling wrap and refrigerate overnight. 
2. Next day, with a stand mixer on a dough hook, add in the milk, sugar and yeast and have a quick mix. Then add in the roux, bread flour, salt and unsalted butter. 
3. Mix on low speed until all ingredients are combined. Increase the speed to medium and continue kneading until it passes the window pane test.
4. Divide the dough in 2 and place half of the dough back to the mixer, add in 8g of black cocoa powder and mix on low speed until the cocoa powder is well incorporated. 
5. Place the 2 doughs in separate bowls, cover with cling wrap and let them rise for about 1 hour or until double in size. 
6. Punch the dough to degas and divide the white dough into 4 equal parts; divide the cocoa dough into 4 parts with irregular sizes (to your liking)
7. Roll the cocoa dough into a long strip almost the length of your loaf pan. Flatten the white dough and wrap the cocoa dough. Place it into the loaf pan and repeat with the other dough.
8. Once all dough are in the loaf pan, cover it with a wet tea towel and place it in a warm place and let it rise for about 40 mins. 
9. Preheat oven to 365F. Bake the bread for about 30-35 mins. Remove the loaf from the pan and let it cool completely before slicing.