Step 1: Make the Dough

1. In a large mixing bowl, whisk together bread flour, sugar, salt, and instant yeast.

2. In a separate bowl, combine warm milk and egg, then pour into the dry ingredients.

3. Knead using your hands or a stand mixer on medium speed until the dough starts to come together.

4. Add softened butter and continue kneading for 10–12 minutes until the dough becomes smooth and elastic.

5. Shape the dough into a ball and place it in a greased bowl. Cover with plastic wrap or a damp towel and let it rise in a warm place for about 1 hour or until doubled in size.

Step 2: Prepare the Chocolate Paste
6. In a small bowl, mix cocoa powder and hot water until smooth.
7. Stir in sugar and melted butter to form a thick paste. Set aside to cool.

Step 3: Roll Out and Layer the Dough
8. Once the dough has risen, punch it down to release air.
9. Roll it out into a large rectangle, about ¼ inch thick.
10. Spread the chocolate paste evenly across the surface, leaving a small border.
11. Roll the dough tightly from the short end to form a log.
12. With a sharp knife, slice the log lengthwise down the middle to reveal the swirl.
13. Twist the two halves together, keeping the cut sides up, to form a braided shape.
14. Carefully place the braid into a greased loaf pan.

Step 4: Final Rise & Bake
15. Cover the loaf loosely with plastic wrap and let it rise again for 30–40 minutes.
16. Preheat your oven to 350°F (175°C).
17. Whisk egg yolk and milk together, then gently brush the top of the loaf.
18. Bake for 30–35 minutes, or until golden brown and cooked through.
19. If the top browns too quickly, loosely cover it with foil for the last 10 minutes.

Step 5: Cool and Serve
20. Let the bread cool in the pan for 10 minutes, then transfer to a wire rack.
21. Slice and serve once fully cooled. Enjoy as is or with a slather of butter or jam!