Recipe ingredients and step by step instructions at https://cookingwithfrenchy.com/recipes/vanilla-sponge-genoise-a-base-for-many-cakes/
Sponge cake is a light aerated cake made with eggs, flour and sugar, sometimes leavened with baking powder. Sponge cakes (genoise/genoese), leavened with beaten eggs, originated during the renaissance era and is a base for many cakes such as strawberry cake, naked cake style, festive cake, designer cakes.
The basic whisked sponge cake does not contain any fat. It’s made by whisking eggs and sugar and gently folding in flour (plain or cornflour). This type of cake is also called foam cake, depending on aeration of eggs and heat to rise. Some types of sponge are baked in non greased pans to improve the cake’s rise by allowing the batter to adhere and climb the sides of the pan. If you wish to use this sponge cake to make Swiss roll for example, it is recommended to include baking soda or cream of tartar in the recipe as it makes the sponge softer and more pliable
To make a Genoise like the French do, flour and melted butter are added to the egg mixture for a moister cake.
Sponge cake bases soaks up the flavours from fresh fruits, fillings and custard. Although sponge cake is usually made without butter, its flavour is often enhanced with stock syrup, layered with either, chocolate ganache, buttercream, pastry creams, mousseline creams or other types of fillings and frostings.