Remove everything from the refrigerator to come up to room temperature.
Preheat the oven to 180°C (350°F).
Generously butter 2, 20cm (or 2, 8 inch) spring form pans. If you like you can also use 2, 24 cm (or 2, 9 inch) spring form pans.
Beginning with the sponge layer, sift the flour, baking powder and salt into a medium size bowl.
In another bowl beat the 3 egg yolks with a hand held mixer on medium speed for 3 minutes. Gradually add all but the 2tbls sugar and beat until the eggs become a pale yellow color and the mixture forms a ribbon, about 5 minutes.
Resift the flour mixture into the egg mixture and very gently blend them together. Then add the melted butter. It may look like there is too much flour to go into the eggs but if you measured correctly it will go in, just be gentle and patient.
In a very clean bowl beat the egg whites with a pinch of salt and the remaining 2 tbls. of sugar to the stiff peak stage but they should not be dry.
Fold in 1/3 of the beaten egg whites into the beaten egg and flour mixture gently. When incorporated add the rest of the egg whites and fold them in gently.
Pour this mixture into the well buttered spring form pan and being sure to evenly cover the bottom of the pan.
Bake in the middle of the oven at 180°C, (350°F) for 10 minutes. This may take a minute or two more or less. So keep an eye on it, it should only become a light golden brown. It will puff up but when you remove it from the oven to cool it will go back to looking like a sponge that you are more familiar with. When baked remove from the oven and cool on a rack. Do not remove the sponge from the pan.