Source: “The All-Purpose baking cookbook” de The King Arthur Flour Baker’s Companion
Note: To make a chocolate genoise, cut the amount of flour to 1/2 cup and whisk it together with 1/4 cup Dutch–process cocoa before folding in into the egg-and-sugar mixture.
- 6 large eggs
- 1 egg yolk
- 3/4 cup superfine or granulated sugar (superfine is best)
- 1/8 teaspoon salt
- 3/4 cup unbleached all-purpose flour
- 1 tablespoon cornstarch
- 4 tablespoons butter melted and slightly cooled
- 2 teaspoons vanilla or almond extract
- Preheat the oven to 350 F.
- Grease (beurrer) and flour two 9-inch round pans; three 8-inch round pans; a 10 X 15-inch jelly roll pan, or a 9 X 3 inch springform pan.
- Place the room-temparature eggs and egg yolk, 1/2 cup of the sugar, and the salt in a heatproof bowl and immerse the bottom of the bowl in warm water. Whisk over the warm water until the sugar dissolved; you’ll be able to feel if the sugar has dissolved by robbing a small amount of the batter between your fingers- it shouldn’t feel gritty. Check the temperature of the batter occasionnally; don’t let it go over 110 F, as the eggs may begin to cook. You’re after batter that’s just warm to touch.
- Once the sugar ha dissolved, remove the bowl from the hot water. Using an electric mixer, beat the egg mixture on high speed until it becomes very light and fluffy. This will take up to 10 minutes. It should double (or more) in volume and be very thick.
- Whisk together the flour, cornstarch, and remaining 1/4 cup sugar to eliminate any lumps and aerate the mixture.
- Using very low speed on an electric mixer, or a hand whisk, gently fold the flour mixture into the eggs, about a third at a time.
- Stir together the butter and extract; mix about a third of the flour-and-egg mixture into the butter, then fold that back into the remaining batter.
- Spoon or pour the batter into the prepared pans, smooting the surface.
- Bake the 8- or 9-inch round layers for 20 to 25 minutes, the jelly roll for 14 to 18 minutes, or the springform for 30 to 35 minutes. All should be light golden in color and spring back when touched lightly in the center. Allow to cool in the pans for 15 minutes.