Combine the walnuts, 1 tsp cinnamon and 2 TB sugar together and set aside.
Mix the butter, sugar and eggs together until fluffy. Blend in the sour cream.
Sift the flour, soda and baking powder together. Mix into the creamed mixture and blend well. Add the vanilla.
Spoon half of the batter into a greased and floured tube or bundt pan. Sprinkle half of the cinnamon mix over the batter (the batter will be thick). Spoon in the remaining batter and top off with the remaining cinnamon mix.
Place the pan in a COLD oven. Set to 350 degrees, then bake for about 55 mins until a toothpick comes out clean.