In the bowl of the mixer, add the yeast, 1 tablespoon of sugar and warm water. Mix lightly and cover with a dish towel for 10 minutes for yeast to activate
Add the sugar, egg, oil, flour, and salt and mix using your dough hook on medium speed until the dough comes together. If dough is too liquid or too sticky, add more flour, 1 tablespoon at a time
When dough comes together and is soft and elastic, remove from mixer and place in a greased bowl. Cover with a dish towel and let it rise for 90 minutes(or until doubled its size) in a warm area
For Filling
In a bowl, combine the water, oil, and cocoa powder and confectioners sugar. Whisk until combined.
Assembly
Divide the dough into 6 equal portions and shape into balls. Cover with a dish towel
Take one ball and roll into a narrow rectangle. Using a spoon or brush, add some of the liquid filling in the to the rectangle leaving a small border, then sprinkle the chocolate chips on top
Roll this strip into a log (it will be a bit messy), and repeat this step with the other 5 dough balls
Place 6 dough strips side by side, and using your fingers, unite the tops. Braid
Place challah in a cookie tin lined with parchment paper and let the dough rest for 90 minutes
Preheat oven to 350 degrees Fahrenheit
Brush the top of the challah with the beaten egg. If you'd like, add some chocolate chips in the nooks and crannies
Bake for 35-45 minutes or until the top of has browned
Remove from the oven and place on a rack until completely cooled