Make the dough: In a medium-sized microwaveable bowl, stir the milk, butter, sugar, and salt. Microwave for 1 minute, until the mixture is about 85-90°F (you can test this with a thermometer). Transfer the mixture to the bowl of your stand mixer fitted with the paddle attachment.
Add the yeast and stir once or twice. Let sit 5 minutes.
Add 2 cups of the flour to the mixture and stir over medium speed until the flour is fully incorporated and the dough is very runny.
Switch the paddle attachment for the dough hook and slowly add the rest of the flour (⅓ cup at a time) and the salt. Stop to scrape down the sides of the bowl in between each addition. Once the dough starts to come together and the dough is coming away from the sides of the bowl enough flour has been added.
Set your stand mixer to medium speed and allow the dough to knead for 3-5 minutes until it is shiny and soft. Pick up the dough and lightly grease the bowl with oil. Place the dough back into the bowl, spritz with additional oil, cover with a piece of plastic wrap or a towel & allow the dough to rise for 1 ½ hours or until it has doubled in size.
To make the filling: In a mixing bowl, combine the brown sugar, softened butter, cocoa powder, espresso powder, vanilla extract, and cinnamon and stir until it forms a paste. Spray a 9x13 baking pan with non-stick spray and set aside.
To shape the rolls: Once the dough has doubled in size, turn the dough out onto a clean dry surface. Roll the dough out until it measures 18 x 26 or about double the size of the baking dish. Using a spatula, spread an even layer of the chocolate filling onto the dough, making sure it reaches all the way to the edges.
Using a pastry cutter or a pizza cutter, cut 12 equal strips, about 2 inches wide. Roll up each strip so it resembles a roll and transfer it to the prepared baking dish repeating this process until all 12 rolls are in the dish. Cover and allow the rolls to rise for about 30 minutes.
Preheat the oven to 350°F. Remove the cover and place them in the center rack of the oven. Bake for 35-40 minutes or until golden brown.
To make the icing: In the bowl of your stand mixer with the whisk attachment, add the cocoa powder, espresso powder, and half of the powdered sugar. Whisk to combine. Add the vanilla extract and 2 tbsp of milk. Stir to combine. Slowly add the rest of the powdered sugar until fully incorporated. Add in the milk, 1 tablespoon at a time, until you reach your desired consistency.
Once the rolls have finished baking, remove them from the oven and allow them to cool for 10 minutes. Drizzle the tops with the chocolate espresso icing and serve warm. Enjoy!