I think. I found a very detailed explanation of 'biscuit' and 'génoise' on this website, Joyce. I hope it helps!

Good luck!


Sheila

En pastelería para elaborar un pastel/ tarta, de cumpleaños por ejemplo (horneado y con levadura) que ulteriormente se decora, de manera genérica se habla de fond de biscuit o génoise tal como lo mencioné antes.

Un bizcocho muy conocido en francés que se queda con el nombre de biscuit: le biscuit de Savoie.


GENOISE OR BUTTERSPONGE:

Genoise, a foam type cake, like an Angel Food Cake, is the classic, fine-crumbed French sponge cake. It has been one of the most prized elements in the French chef's repertoire. It is made by beating warm whole eggs with sugar until the mixture more than triples in volume, then folding in the flour and sometimes melted butter too.

A NOTE ABOUT MY GENOISE CAKE RECIPE: A lot of bakers have trouble making Genoise Cakes and I did a lot of research into why! All of my tips and techniques have been written into my step-by-step recipe to ensure better success in making this types of recipes! Take a look!

Learn how to make a perfect Genoise Cake, step-by-step!!

The Genoise is different from American sponge cakes in that it has less sugar and sometimes contains clarified butter (butter that has been melted so that the water evaporates and the milk solids drop to the bottom. The milk solids then brown which adds a richer flavor). The butter makes the cake somewhat more moist and flavorful. It tends to be dry and usually some type of syrup or icing is added to the finished cake in order to moisten it.

Genoise is one of the most useful cakes because it is firm and sturdy. Because of its plain crumb, it makes a great foundation cake for both elaborate or simple concoctions, such as wedding cakes, layer cakes, tortes, ice cream cakes, Baked Alaska, ladyfingers, petits fours and simpler desserts, filled with buttercream or pastry cream and then fruit. It is a great cake to frost with cream frosting, or whipped ganache.

A genoise is used quite often when making petits fours or small cakes. They usually contain 3 layers of genoise, liberally laced with spirits, and are filled with lemon, hazelnut or raspberry and topped with marzipan. They are then dipped in pastel-colored white chocolate or a fondant glaze.

http://www.baking911.com/cakes/chiffongenoise.htm


The Jelly Roll Cake, also known as a Biscuit Roulade, is typically made from a foam cake.

A jelly roll cake (American), also known as a biscuit roulade, roulade (Paupiette) or biscuit recipe (French) or Swiss Roll (English), is used to refer to cakes that when flat, serve as a base to be filled with another ingredient. They are then rolled into a tube-like or log shape and sliced to display the ingredients swirled into the rolled base of food.

A Roulade is a French term for a thin roll of meat or cake around savory or sweet fillings.

Cake rolls are typically baked in a jelly roll pan, also known as a sheet pan, which is a large and rectangular pan with shallow rims. The type of cakes used are foam cakes, such as a sponge, which is flexible enough to withstand being rolled without cracking. Biscuit Roulade and ladyfingers are types of sponge cakes. But, any type of flexible cake base can be used.

To make the cake base, the batter is spread into a thin layer in a jelly roll pan, baked until firm but still moist. Some cakes are cooled flat or rolled immediately and cooled so the cake forms a log shape. The cake is filled or carefully unrolled if first cooled into a shape and then filled, and rolled tightly. (The Swiss Roll is baked thicker than the other types of rolls and as a result isn't rolled as tightly. )

Cakes fall into two major groups: shortened (fat) cakes and foam cakes (little or no fat).

http://www.baking911.com/cakes/biscuitroulade.htm