Preheat oven to 375.
Lightly grease an 8-inch cake pan with non-stick spray; set aside.
Separate dough into 8 rolls and unroll.
Brush each piece of dough with melted butter.
In a small bowl, mix together cinnamon and sugar.
Evenly divide and sprinkle a generous amount of cinnamon-sugar over each roll.
Evenly divide chopped chocolate and spread over cinnamon-sugar.
Carefully roll up each dough, pinching seams together.
Arrange the rolls 1 inch apart in the prepared cake pan.
Bake for 15 to 17 minutes, or until tops are golden brown.
In the meantime prepare the vanilla glaze.
Place milk, vanilla, and powdered sugar in a small saucepan and cook over medium-heat, stirring constantly just until combined and no lumps appear.
Remove cinnamon rolls from oven and immediately brush rolls with prepared glaze.