Rich cake with a butter icing.
1 Mix together the cake mix and eggs. Fold in the sour cream. Mix in the vanilla, 1 cup sugar, oil and pecans.
2 Pour half of batter into a 9 x 13 inch pan. Combine the ground cinammon and brown sugar. Sprinkle over the batter. Pour the other half of the batter over top.
3 Bake at 350 degrees F (175 degrees C) for 50 minutes.
4 To make Icing: Bring to a boil 1/2 cup butter or margarine, 1 cup sugar, buttermilk and baking soda. Prick cake all over with fork and pour hot icing on cake.