The name 'biscuit' has many different meanings. In the U.S. a biscuit commonly refers to a quick bread leavened with baking powder, baking soda, sometimes a little yeast, or even simply leavened by the introduction of air (beaten biscuits). In the U.K., a biscuit refers to small cookies or crisp breads.

In traditional French bakeries, a biscuit (hear the pronunciation here ) is a thin, sponge-like cake used in layered desserts or used as the sides for mousse cakes. Biscuit sponge cakes contain no leavening, and rise by the introduction of folded whipped egg whites. Depending on the recipe formulator (okay, the pastry chef making the dessert) the biscuit cakes can be thick, thin, dense, or airy - all dependant on the desired finished result or the needs for the finished cake.

Biscuit Sponge Cakes Are Multi-Taskers

Biscuit cakes are common to those who use them and are indispensable as they are multi-taskers in the bake shop. I have a biscuit recipe for just about every pastry application.

Image above is an example of a mousse cake using biscuit sponge cake. Image courtesy Flickr User avlxyz through a creative commons license.

The batter for these sponge cakes are spread onto sheet pans, which are used whole in sheet cakes or cut into strips for the sides of mousse cakes. They can also be piped out into whatever shape is needed, such as piping them into round disks for the inside layers of mousse cakes. The procedure is typically the same for each recipe. A meringue is folded into other ingredients which could be a paste made of egg whites and other ingredients, or egg yolks beaten to a thick ribbon stage. If melted butter is used, it is usually folded in at the very end, as is any chopped nuts. If flour or other dry ingredients are used they are folded in gently as to keep the volume of the meringue.

Below is a list of biscuit sponge cake names and their definitions, which may differ from your kitchen.

List of Common Biscuit Sponge Cakes and Their Definitions

• Biscuit Cullier
  This biscuit sponge is for making traditional Lady Fingers, and is typically piped out prior to baking.
• Biscuit Décor
  Typically very dense and used for the sides of mousse cakes, this biscuit is decorated with thinly scraped and colored pâte à cigarette. The use of special molds for creating different designs.
• Biscuit Financier
  Financiers are small almond-based cakes. Recipes for biscuit financier are typically dense, contain almonds, and sometimes contain melted butter.
• Biscuit Flourless Chocolate
  Special chocolate biscuit sponge cake containing no flour. Recipes either call for melted bittersweet chocolate or cocoa powder.
• Biscuit Joconde
  Traditional biscuit recipe containing almonds and melted butter.
• Biscuit Moelleux
  This biscuit is typically thicker and softer. It is used for both roulades (rolled cakes) and for sheet cakes.
• Biscuit Noisette
  Thin sponge cake made with hazelnuts. Recipes sometimes call for hazelnut powder (ground up hazelnuts) or a hazelnut paste.
• Biscuit Noix
  Thin sponge cake made with walnuts (generally ground up).
• Biscuit Roulé (or Roulade)
  This biscuit cake can be flavored (vanilla, chocolate, lemon, etc.) and is used in the production of roulades, or rolled cakes.
• Biscuit Sacher
  This chocolate flavored biscuit cake is used for building Sacher Cakes.
• Biscuit Success
  Thin sponge cake made predominately of meringue - can be crisp or more soft, depending on the recipe and application.