24 lemon balm leaves
6 extra large eggs
4 extra large egg yolks
2 cups granulated sugar
2 1/2 cups unbleached white flour
1/2 teaspoon salt
16 tablespoons unsalted butter, melted
Zest from 1 lemon
Preheat oven to 375 degrees F and generously butter and lightly flour a 13 x 9-inch baking pan. Arrange part of the lemon balm leaves in the bottom of the baking pan, reserving the remaining leaves for the cake.
Combine eggs, yolks and sugar in the bowl of an electric mixer and beat until pale yellow and very thick. Sift the flour with the salt three times. Slowly fold the flour into the egg mixture, a third at a time. Carefully fold the melted butter into the batter in thirds. Fold in the lemon zest and reserved lemon balm leaves. Bake the cake in the center of the oven until the top is a pale golden brown and a cake tester comes out clean, about 35 to 40 minutes. Do not overbake.
Cool the cake completely before removing from the pan. Sprinkle the inverted cake lightly with vanilla sugar
Serve plain or with whipped cream if desired. Garnish with lemon balm and lemon slices.