Prep. Preheat the oven to 375˚F. Lightly grease an 8-inch cake pan with non-stick spray; set aside.
Make the cinnamon sugar. In a small bowl, mix together the cinnamon and sugar.
Prepare the dough. Separate the dough into 8 rolls and unroll them. Brush each piece of dough with the melted butter.
Add the filling to the dough. Evenly divide and sprinkle a generous amount of the prepared cinnamon-sugar over each unrolled piece of dough. Then, sprinkle the chopped chocolate over the cinnamon-sugar.
Roll them up and bake. Carefully roll up each piece of dough, pinching the seams together. Arrange the rolls 1 inch apart in the prepared cake pan and bake for 15 to 17 minutes, or until the tops are golden brown.
Make the glaze. Meanwhile, combine the milk, vanilla, and powdered sugar in a small saucepan and cook over medium heat, whisking constantly just until combined and no lumps appear. Remove from heat.
Finish and serve. Remove the cinnamon rolls from the oven and immediately brush the rolls with the prepared glaze. Serve.