Method
1. Combine the flour, sugar, yeast and zest in the bottom of the bowl of a stand mixer
2. Add eggs and 1/2 cup water, mixing with the dough hook until it comes together
3. With the mixer on low, add the salt, then the butter, a spoonful at a time, mixing until it’s incorporated into the dough
4. Then, mix on medium speed for 10 minutes until dough is completely smooth
5. Coat a large bowl with oil
6. Place dough inside, cover with plastic and refrigerate
7. Leave in fridge for at least half a day, preferably overnight
8. Make filling: Melt butter and chocolate together until smooth
9. Add powdered sugar, cocoa powder and ground cinnamon to the chocolate mixture; Stir until smooth then set aside
10. Coat two 9-by-4-inch (2 1/4 or 1kg) loaf pans with oil or butter, and line the bottom of each with a rectangle of parchment paper
11. Take half of dough from fridge (leave the other half chilled). Roll out on a well-floured counter to about a 10-inch width (the side closest to you) and as long in length (away from you) as you can when rolling it thin, likely 10 to 12 inches.
12. Spread half of chocolate mixture evenly over the dough, leaving a 1/2-inch border all around. Brush the end farthest away from you with water
13. Roll dough into a log, slice dough into halves with chef's knife
14. Twist sides around each other, with cuts facing upward
15. Transfer dough to prepared pan and repeat with the second batch
16. Cover with kitchen towel and let rise - 1 hr
17. Pre-heat oven - 190°C
18. Bake until lightly browned - approx 30 min, 190°C
19. While babkas are baking, make syrup: Bring sugar and water to a simmer until sugar dissolves
20. Remove from heat and set aside to cool somewhat. As soon as the babkas leave the oven, brush the syrup all over each
21. Let cool about halfway in pan, then transfer to a cooling rack to cool the rest of the way before eating