What is a génoise?
A génoise, also known as Genoese cake or Genovese cake, is an Italian sponge cake named after the city of Genoa and associated with Italian and French cuisine. Instead of using chemical leavening, the air is suspended in the batter during mixing to provide volume.
Genoise should not be confused with 'pain de Gênes' (Genoa bread) which is made from almond paste, but it is similar to 'pan di Spagna' (Spanish bread), another Italian sponge cake.
It is a whole-egg cake, unlike some other sponge cakes for which yolks and whites are beaten separately. The eggs, and sometimes extra yolks, are beaten with sugar and heated at the same time, using a 'bain-marie' or flame, to a stage known to patissiers as "ribbon stage".
A genoise is generally a fairly lean cake, getting most of its fat from egg yolks, but some recipes also add in melted butter before baking. Genoise is a basic building block of much French pâtisserie and is used for making several different types of cake. The batter usually is baked to form a thin sheet.
When finished baking, the sheet is rolled while still warm (to make jelly rolls or 'bûches de Noël'), or cut and stacked into multiple layers or line a mold to be filled with a frozen dessert. A variety of fillings are used, such as jelly, chocolate, fruit, pastry cream, and whipped cream.