Heat the milk in a small saucepan until it reaches 110°F. Sprinkle the active dry yeast into the milk and stir to combine. Let sit for about 10 minutes until frothy.

In a large mixing bowl, whisk together the flour, cocoa powder, sugar, and salt. Add the butter and mix until clumpy. Pour in the yeast mixture and add the eggs, mixing until a soft dough forms. Knead for about 5 minutes.

Transfer the dough to a lightly oiled bowl, cover it, and let rise in a warm place for about 1 hour.

Prepare the filling by beating together butter, brown sugar, and cocoa powder until smooth. Fold in chopped chocolate.

Roll out the dough into a rectangle about 1/4-inch thick. Spread filling over it and roll tightly from one long side to the other. Slice into 12 pieces.

Grease a baking pan and arrange rolls close together. Cover and let rise for about 25 minutes.

Preheat oven to 350°F and bake for 25-30 minutes until golden brown and internal temperature reaches 160°F.

Prepare the icing by mixing powdered sugar, cocoa powder, vanilla, and cream until smooth. Drizzle over rolls after cooling for 10 minutes.