Sponge Cake with Buttercream Frosting
- 2 tablespoons vegetable shortening
- 5 eggs , separated
- 1 tablespoon lemon juice
- 1 cup sugar
- 1/4 teaspoon salt
- 1 cup flour
- 6 tablespoons butter , softened
- 1/4 cup plus 2 tablespoons milk or cream
- 2 teaspoons vanilla
- Pinch of salt
- 1 box (3 3/4 cups) confectioners' sugar
- 2 squares bitter chocolate
Beat the egg yolks with the lemon juice until thick, about 10 minutes. Gradually add 3/4 cup sugar and beat until it is dissolved, about 10 minutes. Set aside.
In a separate bowl, beat the egg whites until foamy; add the salt and continue beating until soft peaks form. Slowly add remaining 1/4 cup sugar; beat until stiff but not dry. Fold 1/4 of the beaten whites into the yolk mixture. Spoon the remaining whites over the yolk mixture and sift the flour on top. Gently fold only until blended.
Spoon the batter into the pans. Bake about 25 minutes, or until a toothpick comes out clean. Invert the pans on a rack and let cool completely, about 30 minutes.
To make the frosting: Beat the butter, milk, vanilla, and salt in a medium bowl. Slowly add the confectioners' sugar; mix until thick and creamy. Beat on high, 5 to 10 more minutes. Frost the top of one cake layer; stack the other on top and frost all around. Melt the chocolate in a double boiler and drizzle over the iced cake.