|Sifted cake flour||1 Cup (16 tbs)|
|Baking powder||1⁄2 Teaspoon|
|Eggs||3 , separated (At Room Temperature)|
|Sugar||2⁄3 Cup (10.67 tbs)|
|Grated orange rind/1 teaspoon grated lemon rind||1 Tablespoon|
|Fresh orange juice/1/4 cup water, plus 1 teaspoon vanilla||1⁄4 Cup (4 tbs)|
Preheat the oven to 350 degrees.
Lightly grease the bottom (not the sides) of a 9-inch cake pan.
Cut out and place a circle of waxed paper in the bottom of the pan.
Set pan aside.
Sift together the flour, baking powder, and salt.
Set aside briefly.
Beat the yolks with an electric mixer 2 to 3 minutes, until they are pale yellow.
Sprinkle on the sugar and continue beating 5 minutes longer, until yolks are thick in texture and quite pale.
Using a spoon, stir the orange rind and orange juice into the thickened egg yolks.
Gradually stir in the sifted flour mixture.
Beat egg whites until peaks that are stiff but not dry form.
Stir 1/4 of the beaten egg whites into the sponge cake batter to lighten it.
Then, very gently, fold in the remainder of the egg whites.
Pour into the prepared pan, and bake, in the lower third of the oven, about 35 minutes, or until done.
The cake should spring back when center is gently pressed with a fingertip.
Let cake cool down in the pan for about 10 minutes.
Turn out, remove waxed paper, and let cake cool on a wire rack.