Preheat oven to 325 degrees F. Spray the six cavities of a mini Bundt pan (4x2 inch) with Baker's Joy. Alternatively, line about 8 or 9 jumbo muffin cups with Reynold's 3 ½ inch foil liners.

Prepare nut mixture first. Stir together nuts, brown sugar and cinnamon. Set aside.

Mix together the sifted cake flour, baking powder and salt and set aside.

In a mixing bowl, cream the butter and sugar using high speed of an electric mixer for about 2 minutes. Add the egg and beat until incorporated. Beat in the vanilla, then fold in the sour cream. Add the flour mixture and stir with a mixing spoon or rubber scraper until it is blended in.

Spoon about a tablespoon of the nut mixture into the cavity of each Bundt pan. Spoon three generously heaping tablespoons (it's thick!) of batter over the nuts. It should come about halfway full. If you are using jumbo muffin cups, sprinkle a tablespoon of the nut mixture on the bottom of each cup, then layer with a heaping tablespoon (or 2 level) tablespoons of batter, another spoonful of nuts and a final heaping tablespoon of batter (it's thick).

Bake for 28 to 30 minutes at 325 F. or until cakes appear set. Let cool for about 5 minutes, then invert from pan and let cool completely. Drizzle with icing if desired.

To make icing, melt 1 tablespoon of butter in a small bowl or 2 cup liquid measuring cup (such as a Pyrex). Stir in 1 cup of confectioners' sugar, then add ¼ teaspoon of vanilla and 1 teaspoon of water. Stir well and keep adding water 1 teaspoon at a time and stirring with a fork until icing is thin enough to drizzle but not so thin it flows all over the place.