Preheat oven to 350°F

In a large bowl, beat oil, sour cream, eggs, and vanilla extract with an electric mixer on medium speed until fully blended.

Sift the cake mix into a medium bowl and pour the cake mix into the bowl with the batter (alternatively, you can sift the cake mix directly into the wet batter). Beat for about 2 minutes, and scrape the bowl occasionally to fully incorporate the ingredients.

Spray the bottom and sides of a 13x9-inch pan with cooking spray.

Pour about half of the batter into the greased pan.

In a small bowl, stir together brown sugar, cinnamon, and orange zest and sprinkle evenly over the batter in the pan.

Carefully pour the remaining batter evenly over the cinnamon-sugar mixture.

With a knife, make swirls in the batter.

Bake in the preheated oven for 30-35 minutes or until golden brown and a toothpick comes out clean.

Prepare Icing. In a small bowl, stir powdered sugar, milk, cinnamon, and vanilla until fully incorporated. Pour and spread the icing over the warm cake and let cool (if you can).

Once cooled, enjoy and feel free to add a comment on my blog! Also, be sure to share your photo on instagram and tag @butterloveandsalt! We would love to see how your cake comes out!