Blend the eggs, egg yolks, and sugar in a mixer bowl with a wire whip attachment until the mixture doubles in volume-about 15 minutes on high speed. Just before stopping the mixer, add the vanilla and mix inches.
Preheat oven to 350 degrees F.
Sift together the cake flour, cornstarch and salt. Fold dry mixture into egg mixture with a wooden spoon or rubber spatula, just until blended.
Coat two 10-inch round cake pans with shortening. Pour the batter into the pans and put them immediately into preheated 350 degree oven.
Bake until tops are springy to the touch, about 45 to 50 minutes.
Remove the cakes from the pans and cool on a wire rack.
When cool, use a long serrated knife to slice off the tops of the cakes.
For tiramisu or other layer cakes, divide each cake into three uniform layers with a serrated knives.