Preheat your oven to 325 degrees
Mix together the cake mix, eggs, sour cream, and oil until well blended.
In a separate bowl, mix together the cinnamon and brown sugar then set aside.
Grease a 9x13 pan and pour half of your cake mixture into the pan. Then sprinkle half of your cinnamon sugar mixture over the cake batter. Next take the remaining cake batter and pour over the cinnamon layer. End with sprinkling the remaining cinnamon sugar mix on top.
Bake for 40-45 minutes or until a toothpick comes out clean.
While the cake is baking, make your glaze. Mix the powdered sugar, milk and vanilla until blended. When the cake comes out, immediately pour the glaze over the hot cake.
You can eat this cake warm or at room temperature. Vanilla ice cream would make a great addition!