Sponge Cake

Preparation

1. Step 1

   Lightly butter a 13 × 7–inch cake pan. Cut a piece of parchment paper or wax paper to fit the bottom of the pan. Fit the paper into the pan and lightly butter the paper. Preheat oven to 325° F.

   Step 2

   In a medium bowl, beat the egg yolks and 2/3 cup sugar with a handheld electric mixer until they turn pale yellow and take on a ribbonlike texture. Beat the lemon juice, lemon zest, and vanilla into the yolks.

   Step 3

   Clean the beaters well, or the egg whites will not whip properly. In a separate, large bowl, whip the egg whites with the salt until foamy. Continue beating, gradually adding the remaining sugar, until the whites form soft peaks when the beaters are lifted from them. With a large rubber spatula, scrape egg-yolk mixture over whites. Fold the yolks gently into egg whites by scraping along the bottom of the bowl and up through the center of the mixture. Fold until just a few streaks of white remain. Sift the flour over the egg mixture and fold it in gently.

   Step 4

   Scrape the batter into the prepared pan. Bake until the top is golden brown and the cake begins to pull away from the sides of the pan, about 30 minutes. Remove, and cool in the pan on a wire rack 20 minutes. Invert the cake onto the rack, and cool completely before removing the paper.