Genoise, a sponge cake, serves as the base for petits fours and other shaped cakes. It is a traditional building block for rolled cakes (also called roulades) such as the Chocolate-Rum Swiss Roll and Jelly Roll.

Genoise relies on eggs beaten with sugar until thick and voluminous. This process relaxes the egg proteins, enabling the eggs to whip up higher and more quickly. It also melts the sugar, resulting in a fine-crumbed cake.

The key to a light genoise is air -- when it comes time to whip the eggs, the more air you incorporate, the lighter the genoise will be. Be sure to beat them on high speed until they are pale white, doubled in volume, and hold a thick ribbon.

Hints For Retaining Volume

• Handle all the ingredients with care.
• Add the flour by lightly sifting it over the beaten egg mixture.
• Fold gently with a large flexible spatula.
• Melt and cool the butter completely before pouring it down the sides of the bowl -- warm butter will cause the mixture to collapse.