1Preheat oven to 350 degrees F. Grease an 8-inch round cake pan with vegetable spray. An alternative is to butter and flour the cake pan. In a medium bowl, whisk together the cornmeal, cake flour and baking powder and set aside.
2Using a stand mixer with a paddle attachemnt, beat the butter and almond paste on high speed until smooth, about 5 minutes. Reduce speed to low and slowly add confectioners' sugar. Mix until thoroughly combined and light and fluffy. Raise speed to high and add the vanilla extract, whole eggs and yolks. 1 at a time. Mix until well combined. Reduce speed to medium and add the sour cream and dry ingredients and mix until just incorporated.
3Pour the batter into the prepared cake pan and smooth the surface with a spatula. Bake in the lower third of the oven for 35 minutes, or until the cake is golden and pulls away from the sides of the pan. Transfer pan to a wire rack and let cool. Remove from pan and dust with confectioners' sugar.