This is very good, but also very fattening!
1 Mix together the cake mix, sugar, oil, eggs, pecans, and vanilla. Fold in the sour cream.
2 Put half the batter in a bundt pan.
3 Mix the brown sugar and cinnamon and sprinkle over the batter in the pan. Pour the remainder of the batter on top.
4 Bake at 350 degrees F (175 degrees C) for 70 minutes until cake tests done.