Make the brioche dough
Mix lukewarm milk, yeast, and sugar with flour until fully combined. Add butter a few pieces at a time, then mix on high speed for 8 minutes until smooth.
Proof the dough
Let the dough rise overnight in the fridge. Cold dough will be much easier to work with and assemble into a babka.
Make the filling
Make the chocolate tahini filling by melting the butter in a saucepan, then adding in the sugar until dissolved. Stir in the chocolate, cocoa powder, and tahini.
Assemble the babka
Roll the dough out into a rough rectangle and spread the chocolate tahini filling all over. Roll the dough up from the short side and freeze for 20 minutes.
Braid the babka
Cut the ends of the rolled up dough off then cut all the way down the middle. Turn each piece upwards and braid them together.
Proof the babka
Place the assembled babka in a loaf pan and rise for one hour in a warm environment.
Bake the babka at 350 degrees F for about 40 minutes, then immediately brush on the sugar syrup.
Slice and enjoy!
Get the full recipe on AtSloanesTable.com.