Preheat oven to 180 degrees C. Grease and flour a ring tin. Sift together the flour, bicarb soda and salt. Set aside.
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 sour cream and vanilla. Beat in the flour mixture until well blended. Pour batter into prepared pan.
Pour half of batter into prepared ring tin. Sprinkle with cinnamon, brown sugar and nuts. Pour in remaining batter.
Bake in the preheated oven for 90 minutes, or until a skewer inserted into the centre of the cake comes out clean. Let cool in pan for 10 minutes, then turn out onto a wire rack and cool completely.