A basic sponge cake recipe calls for eggs, sugar, flour and salt. Vanilla and lemon extract add flavor, while cream of tartar stabilizes the egg whites. This recipe requires a 9-inch round cake pan and takes approximately one hour to make.
To prepare the egg mixture, gather four eggs, 2 tablespoons of sugar, 1/4 teaspoon of salt and 1/2 teaspoon of vanilla extract together. Set aside 1/2 cup of sifted cake flour, 1/2 cup of sugar, 1/2 teaspoon of lemon extract and 1/4 teaspoon of cream tartar. Break the eggs into one of two bowls, remove the yolks, and put the yolks in the remaining bowl. Add the sugar to the yolks bit by bit as you mix until a light texture forms. Once light, pour the lemon and vanilla extracts into the mixture, and place the bowel in a safe place.
Next, mix the egg whites well, and add the cream of tartar and salt. Preheat the oven to 325 degrees Fahrenheit, and grease the bottom of the pan. Spread the parchment paper over the greased bottom. Combine the yolk mixture with the egg-white mixture, add the cake flour, pour the mixture on the pan, and place the pan in the oven. Cook the mixture for approximately 35 minutes before cooling and serving.