1. To make the batter, mix together cake mix, oil, eggs, and sour cream.
2. Pour half of the batter into a greased 9x13 pan.
3. In a small bowl, work together cinnamon and brown sugar.
4. Sprinkle over batter evenly.
5. Plop on the remaining batter over the cinnamon sugar mixture, and spread evenly.
6. Using a knife, swirl together batter and cinnamon!
7. Bake at 325°F (160°C) for 40 minutes.
8. Whisk together powdered sugar, milk, and vanilla to make the glaze.
9. Poke a few holes into the warm cake, and drizzle over the glaze!
10. Serve warm! 😋
