Preheat oven to 350 degrees F (175 degrees C). Lightly grease one 10 inch tube pan.
In a large mixing bowl cream together the butter or margarine and 2 cups of the sugar until fluffy. Add the vanilla and the eggs one at time beating mixture well after each egg.
Combine flour with baking powder and baking soda. Add alternately with sour cream to egg mixture. Beating just enough after each addition to keep batter smooth.
Combine walnuts, cinnamon, and remaining 3/4 cup of sugar.
Spoon 1/3 of the batter into prepared pan, sprinkle with 1/3 of the walnut mixture. Repeat layers two more times.
Bake at 350 degrees F (175 degrees C) for 70 minutes or until center is done. Let cake cool in pan for 10 minutes then remove pan and let cake continue cooling on a wire rack.
