Preheat oven to 350 and grease a 9x13 pan.
Mix cake mix, eggs, oil, sugar, and sour cream until blended.
Pour half of the batter in the pan.
Combine brown sugar and cinnamon and spread over cake batter.
Spread the rest of the cake batter on top of brown sugar mixture.
Bake for approximately 40 minutes.
Mix powdered sugar, vanilla, and milk.
Once cake is cooled, pour glaze on top of cake.