First make the filling. In a food processor, add the walnuts and chocolate and pulse together until the nuts and chocolate are fine, but not powdery They should still have some texture to it. Add to a bowl along with the brown sugar and cinnamon and mix together. Set aside.
In the bowl of a stand mixer, add 1 cup warm water, yeast and sugar. Mix lightly with a fork to get all the yeast in the water and set aside for about 15 minutes. It should begin to foam up and you should see little bubbles.
Next, add eggs, oil and honey, vanilla paste and whisk together.
Using a dough attachment on your mixer, gradually add sifted flour and salt, about 1/2 cup at a time with the mixer on low. Continue to mix until everything is incorporated. The dough should begin to pull away from the bowl and come to 1 large ball of dough.
Turn the dough onto a very well floured surface and knead for about 5 minutes. You can use your finger to see if it's ready. Press your finger in and if the dough bounces back quickly, it's ready.
In a large bowl, pour a bit of oil in and place your dough ball in the bowl. Turn it around so the entire dough is covered with a thin layer of oil. Cover with a clean towel and place bowl in a warm spot. (for me, it was my oven). Allow to rest and rise for 1 1/2hours until doubled in size.
When dough is ready, it should have doubled in size. Punch the dough down and knead a bit to soften. Divide dough into 2 balls, this will be your challahs. Cover 1 ball of dough as you work with the other.
Divide the ball into 3 equal strands and roll each strand into a long snake, about 15 inches long. The use a rolling pin to flatten out the strand about 1-2 inches thick and spread the chocolate and walnut filling within the strand and pinch to seal ends.
if you had trouble like me, instead of braiding the challah, wrap it in a tight circle so the filling stays enclosed.
Or, you can ass a few tablespoons of filling to the dough and knead it in a few times so it's worked into the dough, then braid the challah.
Next, place on cookie sheet and allow to rise for another 30 minutes. The brush challahs with egg wash.
When ready, place in pre-heated 350 degree F oven and bake for about 30 minute or until the top is golden brown. Check a few minutes before and if the top is cooking too fast, cover with foil.
When done, remove from oven and allow to cool slightly before cutting the bread.