Génoise

La Chimie du Dessert has the following definition to offer for génoise cake: "A sponge cake confectioned from whole eggs beaten to a froth with sugar. To ensure the cake's proper rising, the eggs are whipped extensively, until they have tripled in volume and fall gently off the beater in ribbons and form ribbon-like ridges when poured into the pan. At this stage, the mousse is thick enough to retain air bubbles. Flour and sometimes melted butter are then added. (The butter moistens the crumb and makes the cake keep longer.)"

This is in translation, of course. In any case, I don't think I can be the only one to get kinds of sponge cake (angel food, which uses no yolks, for instance, or chiffon cake, which uses baking powder) mixed up. It may also be that the definitions themselves are less than crystal-clear. In Craig Claibourne, an out-of-print, Joy-of-Cooking-like favourite cookbook, génoise beats the eggs and yolks separately, then folds the former into the latter, with flour added. This is the exact definition that Chimie gives for sponge cake. The craig citation is from a bûche recipe, whereas Chimie endorses génoise and sponge for rolling purposes. Maybe these are my misnomers, but maybe this is just a mixed-up world for those who can't find a copy of Larousse Gastronomique.

This diatribe on the futility of sponge cake classification has nothing to do with anything. (Purely and self-indulgently tangential paragraphs are a perk of having a blog nobody reads.) My point here is that sponge cake is a fascinating thing. With its myriad forms and facets, it has as many uses as labels. My personal favourite is the bûche de noël, or any roll-up cake. This kind is made with génoise, sponge, whatever, and frosted or at least rolled with something or other. A proper bûche as I've always made it involves mocha cream frosting and rum syrup. The less festive jelly roll's virtues are exually extolled (I doubt their veracity myself, but who can tell) and other prosaic rolled, frosted cakes are of course common.

Your average cake or tea-cake of this kind is baked on a parchment-paper lined cookie sheet, rolled, rested, unrolled, frosted, rerolled, and frosted some more. A fair amount of work, depending on the occasion, goes into this sort of thing. I've seen various spins on the concept: rolled with jam, frosted inside/outside, unfrosted except with decorator's, etc. I admit that the whole shape and assembly is mostly a sleight-of-hand presentation deal. Easier than, say, making chocolate curls (I CANNOT do this) but harder than putting a cherry on top. You want to make a jelly roll? Make a square cake, slice it latitudinally, put jam on the bottom one, and you have a (more visually blah) jelly roll. You want mocha cream frosting on your génoise? Use a regular old 9" by 9" and slather it on.

Rolling cakes is about presentation and occasion: a one-dimensional Christmas log just doesn't do the trick. That means, however, that rolled or not, sponge cake is a star. It's one of those versatile kitchen staples. It's easy to perfume with lemon or citrus rind, notably, although I would like to try--just, you know, to see--using ground tea leaves or matcha. It takes whatever frosting you like (try a simple emulsion of orange juice, rind, a little softened butter and masses of confectioner's sugar to thicken). Brushing with alcoholic or plain sugar syrup adds a pleasing crunch. It can be a foil for fresh fruit or homemade jam.

(N. B. Sponge cake and its affiliated confections are not to be confused with butter cake, though the two have similar-looking end products.)

Besides complicated rolling and slicing procedures, sponge cake follows a basic structure: eggs beaten to maximum fluffiness (the eggs and the yolks are whipped either separately or together, depending, as I've said, on the type of cake), then stabilizing and flavour-giving ingredients (flour, cream of tartar, butter) are delicately folded into the mixture. Think of sponge cakes as sturdy soufflés. Both rise by the same graceful chemical feat, but génoise and its relatives stay souffléd with the help of starch.

Sponge cake (and chiffon, angel and génoise cake, under their correct names or not) recipes are available at every virtual and physical page-turn, so try one and see what happens. They can backbone a show-stopper or be modest, plain and unassuming. Recipes tend to be forgiving, provided the egg whites whip properly, and you can think of them as beginner's soufflés. They're sweet and fluffy, people. Life is short.