Preheat oven to 350 degrees, if using a glass baking dish, preheat to 325.
Butter and flour a 9-inch tube pan or a 13×9 baking dish.
Prepare Cinnamon Nut topping. Set aside.
Sift and measure flour; sift again with baking powder, baking soda, and salt.
Add eggs and vanilla, beating until light and fluffy. Add flour mixture in three portions, alternating with sour cream, beating well after each addition.
Spread half of batter in pan. Sprinkle with half of Cinnamon-Nut Topping. Spoon on remaining batter and sprinkle with remaining topping.
Bake cake in tube pan 45 to 50 minutes. Bake oblong cake 40 minutes. Cake begins to pull away from side of pan when done.
Allow to cool 20 minutes before removing from pan. Serve warm or cooled.