1 box yellow cake mix (Duncan Hines all-butter recipe)
4 eggs
1 (8 oz.) sour cream
3/4 c. oil
1 c. brown sugar
3 tsp. cinnamon

2 c. confectioners' sugar
4 tbsp. milk
1 tsp. vanilla

Mix first 4 ingredients. Pour half of mixture in greased and floured 9x13 inch pan. Sprinkle half of brown sugar mixture over this. Then put remaining batter and rest of brown sugar. Swirl with knife. Bake at 350 degrees for 45 minutes. Pour icing over warm cake.