serves: One 13 x 7-inch cake
7 large eggs, separated
1⅓ cups sugar
2 tablespoons lemon juice, plus 1 1/2 teaspoons
1½ teaspoons grated lemon zest
1½ tablespoons vanilla extract
½ teaspoon salt
1½ cups sifted cake flour
Lightly butter a 13 x 7-inch cake pan. Cut a piece of parchment paper or waxed paper to fit the bottom of the pan. Fit the paper into the pan and lightly butter the paper. Preheat oven to 325 degrees F.
In a medium bowl, beat the egg yolks and 2/3 cup sugar with an electric handheld mixer until they turn pale yellow and take on a ribbon-like texture. Beat the lemon juice, lemon zest and vanilla into the yolks.
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 sugar, until the whites form stiff 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 egg mixture and fold it in gently.
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 on a wire rack 20 minutes. Invert the cake onto the rack and cool completely before removing the paper.