Preheat oven to 325°F (160°C).

Grease and flour a Bundt pan.

Cream together butter and sugar until light and fluffy.

Blend in vanilla extract.

Add eggs, one at a time, mixing well after each addition.

In a separate bowl, sift together flour, baking powder, salt, and cinnamon.

Add nuts and raisins (or dates) to the dry ingredients and coat well.

Gradually add the dry ingredients to the creamed mixture, alternating with sour cream, blending well after each addition.

Pour batter into the prepared Bundt pan.

Sprinkle cinnamon sugar evenly over the top of the batter.

Bake for 60 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for at least 1 hour.

Invert the cake onto a serving plate.

Sprinkle with additional cinnamon sugar or powdered sugar.