In a small saucepan, pour flour, orange juice and mix with a wisk.
Place over low heat and cook, whisking constantly, until the mixture reaches 149F - 65°C.
Refrigerate 12 hours or overnight
The day after, place in the bowl of a stand mixer the sifted flours, yeast, room temperature Tangzhong, orange zest and powder milk.
Knead with hook attachment to combine the ingredients.
Pour the eggs combined with heavy cream and knead, increasing the speed, gradually (4/6 K.A.).
Gradually add sugar and when it is completely incorporated, add the soft butter, a little at a time, then, add salt (the dough should be ready in about 20 minutes).
Weigh the dough and divide in 2 equal parts.
Put one of the parts back into the stand mixer.
In a small bowl combine cocoa powder and add the necessary water to make a batter.
Add the cocoa mixture to the dough in the mixer and knead until it is completely incorporated.
Weigh the cocoa dough and remove some dough (both doughs must have the same weight).
Transfer each dough (orange and cocoa) into 2 different bowls, cover and let it proof at room temperature until it doubles in size.
Deflate the doughs and divide each dough into 4 small balls: balls dough must have the same weight.
In a surface dusted with flour, place a part of orange dough next to a part of cocoa dough
Roll them out with a rolling pin into a rectangular shape and fold 1/3 from right edge to the middle, then 1/3 from the left edge to the middle so that both colors overlap.
Roll out into a rectangle and roll into a cylinder.
Place the dough into a greased loaf pan (24x11x7 cm) and repeat with the rest of the dough, inverting the colors of dough inside the tin.
Cover with clingfilm and let rise until double in size.
Heat fan oven at 300F - 150°C.
Brush the surface with lightly beaten egg and bake for about 50 minutes.
Let cool for a few minutes, then remove the loaf from the tin.
Place on a wire rack util completely cooled.