Preheat oven to 325. Generously butter an 20 cm X 3 cm square baking pan. In a large bowl, combine half cup of the sugar and the butter, egg yolks and orange and lemon zests. Scrape seeds from vanilla bean into mixture, or add extract. Using an electric mixer, beat at high speed until smooth, light and creamy, about 2 minutes. In a food processor, finely grind the almonds with the cornmeal/polenta, cornstarch and baking powder. In a medium bowl, using an electric mixer, beat the egg whites with the remaining quarter teaspoon sugar until they form soft peaks. Gently fold the dry ingredients and half the beaten egg whites into the butter mixture; then fold in the remaining egg whites unti just incorporated. Gently scrape the batter evenly into the prepared pan and bake for about 30 minutes, or until the top of the cake is golden and a cake tester inserted into the center comes out clean. Transfer pan to a cooling rack for 10 minutes; then invert the cake on the rack and let cool completely. Sprinkle with confectioners sugar, cut into 6 pieces and serve with topping. -Richard Sax Recipe By : From Food & Wine 1994