Bring a medium-sized saucepan to medium heat. Add the milk, cocoa powder, and Torani Sweet Heat Syrup. Whisk together until the cocoa powder is dissolved, then add in the cinnamon, vanilla extract, and the bittersweet chocolate. Whisk continuously until the chocolate has completely melted and the mixture is hot, but not boiling. Remove the saucepan from the burner, and divide the hot chocolate into 2 mugs. Serve with mini marshmallows, an extra sprinkle of cinnamon, and cinnamon sticks for stirring. Enjoy!