I just can't wait for Christmas! I have been making this coffee cake for over 40 years and it is a family tradition for Christmas morning. My husband couldn't wait until Christmas this year so I baked a bonus cake in November.
In medium bowl cream softened butter with 1 cup white sugar. Add eggs and mix. Add vanilla extract and mix. I use a hand electric mixer.
In large bowl blend well flour, baking powder, baking soda and salt.
Gradually add sour cream, apple sauce and butter/egg mixture, alternating, to flour mixture and mix with hand electric mixer until well incorporated. Do not over-mix.
In small bowl mix nuts, brown sugar, cinnamon and white sugar until well blended.
Pour 1/2 of cake mixture into a well greased and floured tube or fluted pan. Spread 1/2 of nut mixture over cake. Using a knife do small scrolls, such as an "s" shape, through the nut mixture and into the cake mixture. Do this around the whole pan. Pour balance of cake mixture onto the nut mixture. Again do small scrolls around the cake. Bake in a preheated 350 oven for about 45 minutes.
Remove from oven and let cool for about 15 minutes. Put a plate on top of pan and carefully invert cake and then re-invert onto another serving plate. You will lose some of the topping so do it as carefully as possible.