You will bake a cake on the second day of buche de Noel. The genoise, or sponge cake, will soak up flavors and roll into a log.
This recipe comes from The Fundamental Techniques of Classic Pastry Arts by The French Culinary Institute:
For the French meringue
4 large egg whites, at room temperature
125 grams (4 1/2 ounces) sugar
For the batter
4 large egg yolks, at room temperature, beaten
125 grams (4 1/2 ounces) cake flour, sifted
60 grams (2 ounces) unsalted butter, melted and cooled slightly
Preheat the oven to 177 degrees C (350 degrees F).
[Make an “X” with butter on a half-sheet pan before placing parchment paper on it (to prevent sliding).]
To make the meringue, place the egg whites in the bowl of a standing electric mixer fitted with the whip attachment. Beat on low to aerate. Add the sugar, raise the speed to high, and beat for about 5 minutes, or until a stiff peak forms.
Beat the egg yolks and, using a rubber spatula, carefully fold them into the meringue. Fold the sifted flour into the meringue. Finally, carefully fold the butter into the meringue. The butter should be liquid but not hot, or it will deflate the batter.
Carefully pour the batter into the prepared pan, smoothing it out into an even layer [it will be thin].
Bake the cake for 3 minutes, rotate the pan, and continue to bake for another 4 minutes, or until the surface is an even golden brown and the center springs back when lightly touched.
Carefully invert the cake onto a clean, cold sheet pan or wire rack. Peel off and discard the parchment paper and let the cake cool.
When completely cool, cover your gateau tightly with plastic wrap.