In a large bowl mix together the ground walnuts, sugar and cocoa. {I whizzed the walnuts, cocoa, scraped vanilla bean and sugar in the Thermomix}
Heat the milk and butter to boiling.
Pour the liquid over the nut/sugar mixture.
Add the egg yolk and vanilla and mix thoroughly.
Allow to stand at room temperature until ready to be spread on the dough.
If the mixture thickens, add a small amount of warm milk {This is important}
To Roll and Assemble the Dough:
Spread a clean sheet or cloth over your entire table so that it is covered.
Sprinkle with a couple of tablespoons to a handful of flour {use flour sparingly}
Place the dough on the sheet and roll the dough out with a rolling pin, starting in the middle and working your way out, until it measures roughly 10-12 inches in diameter
Spoon 1 to 1.5 teaspoons of melted butter on top.{I forgot to do this}
Using the tops of your hands, stretch dough out from the center until the dough is thin and uniformly opaque. You can also use your rolling pin, if you prefer.
As you work, continually pick up the dough from the table, not only to help in stretching it out, but also to make sure that it isn’t sticking.
When you think it the dough is thin enough, try to get it a little thinner. It should be so thin that you can see the color and perhaps the pattern of the sheet underneath.
Spoon filling evenly over dough until covered. {It should spread easily else the dough will tear. Mine did as the filling was initially a bit thick}
Lift the edge of the cloth and gently roll the dough like a jelly roll
Once the dough is rolled up into a rope, gently lift it up and place it into a greased loaf pan in the shape of a “U”, with the ends meeting in the middle. You want to coil the dough around itself, as this will give the dough its characteristic look when sliced
Brush the top of the loaf with the beaten egg white and sprinkle with granulated sugar. {Original recipe uses strong coffee instead of egg white}
Cover pans lightly will plastic wrap and allow to rest for approximately 15 minutes.
Preheat oven to moderate 180°C.
Remove plastic wrap from dough and place into the preheated oven and bake for approximately 15 minutes.
Turn down the oven temperature to slow 150°C and bake for an additional 45 minutes, or until done. {Check the bread at 30 minutes to ensure that the bread is not getting too brown. You may cover the loaves with a sheet of aluminum foil if you need to.}
Remove bread from oven and brush with melted butter.
Remove from the oven and allow to cool on a wire rack for 20-30 minutes, still in the bread pan. Remember, the bread is heavy about 2.5 and it needs to be able to hold its own weight, which is difficult when still warm and fresh out of the oven. Allowing it to cool in the pan helps the loaf to hold its shape.
It is recommended that the best way to cut Povitica loaves into slices is by turning the loaf upside down and slicing with a serrated knife.