For the dough:

Place flour, sugar, yeast in a stand mixer with the dough hook attachment and mix on low speed for one minute.

Add eggs, water and vanilla and mix on low speed for a few seconds. Then increase speed to medium and mix for 3 minutes, until the dough comes together.

Add the salt and start adding the butter a few cubes at a time, mixing until it is incorporated into the dough. Continue mixing for about 10 minutes on medium speed until the dough is completely smooth, elastic and shiny.

(A side note: Do not leave your mixer unattended. It was while I was making babka and stepped away during this process and my Grandma’s Kitchen Aid ended up on the floor still spinning with the bowl attached. This is how my tile floor ended up with a 2 inch hole in it. Needless to say, the Kitchen Aid still works fine. Yes, they are worth it. And this one must be over 41 years old, I’ m guessing.)

During the mixing, you will need to scrape down the sides of the bowl a few times and throw a small amount of flour onto the sides so that the dough doesn’t stick.

Place the dough in a large bowl brushed with oil. Cover with plastic wrap and leave in the fridge overnight.

Filling:

Mix together confectioners sugar, cocoa, chocolate and butter. You will get a spreadable paste.

Grease two 9×5 loaf pans and line the bottoms with parchment paper. Divide dough in half and keep one half covered. (I will tell you that my dough was very cold when I took it out of the fridge. I let it warm up before I started rolling it. You don’t want it to warm up too much as the butter will start to ooze out of it
but this made it easier for me to work with.)

Roll out dough on a lightly floured surface into a rectangle measuring 15 x 11. Position the longest side closest to you. Cut off ends to make them even. Spread half the chocolate over the rectangle leaving a ¾ inch border all around. Sprinkle half the nuts on top of the chocolate, then sprinkle on half the superfine
sugar.

Brush a bit of water along the long end furthest away from you. Use both hands to roll up the rectangle like a jelly roll starting from the side nearest you and ending at the long end. Press to seal the damp end and then use both hands to even out the roll into a perfect thick cigar. Rest the roll on the seam.

Trim the ends with a serrated knife. Now use the knife to gently cut the roll in half lengthwise cutting through from the top to the bottom seam. You are essentially dividing the roll into two long even halves with the layers of dough and filling visible along each length. With the cut sides facing up, gently press together one end of each half and then lift the right half over the left half. Repeat the process, but this time lift the left half over the right to create a simple two pronged plait. Gently squeeze together the other ends so you are left with the two halves intertwined showing the filling on top. Carefully lift the loaf into prepared pan. Cover the pan with a clean damp towel and leave to rise in a warm place for 1 to 1/1/2 hours. It will only rise by 10-20 percent. Repeat for second cake.

Preheat oven to 375.

Remove the towels, place the cakes on the middle rack and bake about 30 minutes or until a skewer comes out clean. They should be golden colored.