01 - Combine flour, cocoa powder, yeast, sugar, and salt in a large mixing bowl.
02 - Add warm milk, melted butter, and egg to the dry ingredients. Mix until a sticky, cohesive dough forms.
03 - Knead by hand on a floured surface or with a stand mixer for 8–10 minutes until smooth and elastic.
04 - Place dough in a greased bowl, cover, and let rise in a warm area until doubled in volume, approximately 1 hour.
05 - Punch down risen dough and roll out on a floured surface into a 16x12-inch rectangle.
06 - Spread softened butter evenly over the entire surface of the rolled dough.
07 - Mix brown sugar, cocoa powder, and cinnamon in a small bowl until well combined.
08 - Sprinkle the sugar-cocoa mixture evenly over the buttered dough, then scatter chocolate chips on top.
09 - Roll up the dough tightly from the long edge into a log. Slice into 12 equal portions and arrange in a greased 9x13-inch baking dish.
10 - Cover the dish and let rolls rise until puffy, about 30–45 minutes.
11 - Preheat oven to 350°F during the final rise period.
12 - Bake for 22–25 minutes until rolls are set and lightly browned.
13 - While rolls cool slightly, whisk together powdered sugar, cocoa powder, milk, and vanilla extract until smooth.
14 - Drizzle chocolate glaze generously over warm rolls immediately before serving.