Mix cake mix, sugar, oil, eggs and sour cream. Beat on medium for 2 minutes. In a small bowl, mix brown sugar and cinnamon. Pour half of cake batter into a greased long baking dish. Sprinkle half of brown sugar mix over batter. Add the remaining batter and sprinkle with remaining sugar mixture. Stir lightly with a knife. Bake at 350 degrees for 35 minutes. Top with a mixture of powdered sugar and milk while hot.
Recipe by The Tennessee Magazine at https://www.tnmagazine.org/letters-to-the-editor-37/