Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch pan.
In a large bowl, cream together the butter and white sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. Combine the flour, baking powder, baking soda and salt; stir into the creamed mixture alternately with the sour cream. Spread half of the batter into the prepared pan.
In a small bowl, combine the brown sugar and cinnamon. Sprinkle over batter in pan.
Spread remaining batter over top. Bake for 30 to 35 minutes in the preheated oven. Cake is done when it springs back to the touch.