Preheat oven to 350 F. Grease and flour 12-cup Bundt pan or 10" tube pan and set aside. Beat butter and sugar in large bowl with electric mixer until light and fluffy. Add poppy seed filling and beat until blended. Beat in egg yolks. 1 at a time, beating well after each addition. Add vanilla and sour cream and beat just until blended. Stir flour, baking soda, and salt until mixed, and add to poppy mixture gradually, beating well after each addition. Beat egg whites in separate bowl with electric mixer until stiff peaks form. Fold beaten egg whites into batter. Spread batter evenly in prepared pan. Bake 50 to 60 minutes or until cake tester inserted in center comes out clean. Cool in pan on wire rack 10 minutes. Remove from pan and cool completely on rack. Dust with confectioners sugar (you won't need to whole amount) just before serving Makes 14 to 16 servings.
I usually use 1/2 tsp vanilla and 1/2 tsp almond extract.
