1 yellow cake mix
1 (8 oz.) sour cream
4 eggs
2/3 c. oil
1 c. brown sugar
1 tbsp. cinnamon
1/4 c. milk
2 tsp. vanilla
2 c. powdered sugar

Mix together cake mix, sour cream, eggs and oil. Pour in sprayed cake pan. Mix together brown sugar and cinnamon and swirl through cake batter.

Bake cake at 350°F until cake tester comes out clean. Mix milk, vanilla and powdered sugar and pour over cake.