Polenta Cake

Preheat oven to 325 degrees F. Generously butter 8- to 9-inch kugelhopf or Bundt pan.

Place butter, first measure of sugar, egg yolks and citrus zests in large bowl. If using vanilla bean, scrape seeds from pod into butter mixture or add extract. Beat until light and creamy.

In a food processor, combine nuts, starch, cornmeal and baking powder. Process until powdery. Sift this mixture onto sheet of wax paper (if bits of nuts remain in sifter, return them to mixture).

Beat egg whites with remaining sugar until they form soft peaks. Gently fold dry ingredients and half of beaten egg whites into butter mixture, fold in remaining whites just until incorporated. Gently scrape batter into pan.

Bake until cake is golden and a toothpick inserted in the center comes out clean, usually about 40 minutes. Do not over bake.

Cool cake briefly in pan on wire rack. Run the tip of knife around the sides of cake to loosen it from pan, then invert onto rack. Sprinkle with confectioners' sugar.

Serve lukewarm or at room temperature.