This recipe is used to make the genoise layer for the Almond Dacquoise Cake or Raspberry Mousse Cakes with Flowering Maple Blossoms. The layer of genoise and a layer of dacquoise are iced together with whipped ganache to form a neat loaf shape.
Heat oven to 350 degrees. Line a 12 1/2-by-17 1/2- inch baking pan with parchment paper; brush with butter and dust with flour, shaking out excess. Set aside.
In the heat-proof bowl of an electric mixer, combine the eggs and sugar. Set bowl over a pot of gently simmering water; whisk until the mixture feels warm to the touch.
Transfer bowl to the mixer stand. Add vanilla. Using the whisk attachment, whip the mixture on high until light and thickened, about 6 minutes. Sift flour over egg mixture, one-third at a time, folding after each addition. Just before the final third is completely incorporated, fold in the melted butter.
Pour batter into prepared pan. Spread evenly with an offset spatula. Bake until a cake tester inserted into the middle comes out clean, and cake is springy to the touch, about 20 minutes. Transfer to cooling rack.
When cake is cool, invert pan; discard parchment paper. Using a serrated knife, cut cake into two 4-by-7-inch rectangles. Reserve excess cake for another use. Wrap cakes in plastic wrap; set aside (genoise can be made up to a day in advance).