All ingredients should be at room temperature. In bowl mix together flours, soda and baking powder. In another bowl cream together butter with sugar until fluffy and light. Add egg and vanilla and mix well. Add half of dry ingredients, mixing just until flour is blended. Blend in sour cream, then remaining dry ingredients. Spread half of batter lightly into a 10-inch tube pan. Sprinkle with half of Topping and spread with remaining batter. Sprinkle with remaining Topping. Bake at 350 degrees 40 to 45 minutes. TOPPING: Mix together flour, sugar, salt and nuts. Add butter in small pieces. Rub in by hand until mixture is crumbly. Be careful not to over mix. Each serving contains about: 580 calories; 331 mg sodium; 85 mg cholesterol; 34 grams fat; 66 grams carbohydrates; 7 grams protein; .77 gram fiber.