In a large bowl combine cake mix, eggs, milk and oil (or butter) using a hand mixer. Beat at a medium speed for 2 minutes.
Grease two loaf pans with cooking oil.
Add a layer of batter to each, just enough to cover the whole bottom of the bread pan.
In a small bowl, combine sugar, brown sugar and cinnamon. Stir until blended.
Spoon a layer of cinnamon sugar on top of the layer of batter in each loaf pan. Repeat layers until batter and cinnamon sugar is used up. Use a knife to spread out the cinnamon as needed. You can swirl the cinnamon sugar for a marbled look if you want.
Bake at 350˚for 40 minutes* or until toothpick inserted into center of each loaf comes out clean. *Cook time will vary depending on loaf pan size and shape.
When done, let cool for 5-10 minutes then top with icing if desired. Slice and serve warm!