Before starting this Chocolate & Vanilla Layer Cake recipe, organise all the necessary ingredients for the vanilla sponge cake. For the vanilla sponge cake: Place the whole eggs and castor sugar in the stand mixer bowl. Place the bowl over a bain-marie and blanch the ingredients with the whisk, until the preparation is pale and fluffy and reaches a temperature of 50°C. When touching the preparation with the tip of your finger, the heat should be barely bearable. ...