In a large bowl, mix together the flour, cocoa, and salt. Set aside.
In a sauce pan, or microwave, slightly warm the milk. Add the sugar and yeast and let set several minutes until it starts to bubble. Add the melted butter, instant espresso powder, and egg yolk. Set the egg white aside for later.
Mix the milk mixture to the flour until combined. Turn out the dough on to a floured surface and knead for 4 - 5 minutes. Put the dough into an oiled bowl and cover. Let set until double in size, about 1 hour.
After the dough has doubled in size, punch it down and knead a couple of times. Roll dough into a rectangle about 15 x 18 inches. Spread the filling over the dough and roll up. Using a sharp knife, split the roll in to 2 pieces leaving about 1 or so inches connected at the top. Braid the dough by putting one strand over the other. Join ends of the dough to make a circle and place in an oiled skillet or round baking dish. Whip up leftover egg white and brush over the dough.
Bake in a 375 degree oven for 20 - 25 minutes. Let cool slightly and sprinkle with powdered sugar. Enjoy!
*Next time I might add some fresh raspberries before rolling up the dough.