1/4 cup all-purpose flour
2 teaspoons baking powder
1/3 cup unsweetened cocoa powder
1/3 cup water
1/2 teaspoon vanilla extract
Whites from 4 large eggs, at room temperature
Pinch of salt
1/3 cup granulated sugar
For decoration: confectioners' sugar
Heat oven to 350. Have an 8-inch-round cake pan ready. Mix flour and baking powder. Put cocoa and water in a small saucepan over low heat. Bring to a simmer and cook, stirring constantly, about 1 minute until thick and smooth. Remove from heat; stir in vanilla. Beat egg whites and salt in a large bowl with electric mixer until foamy. Gradually add sugar, beating until soft peaks form when beaters are lifted. Quickly add cocoa mixture; beat just until blended. Fold in flour mixture in 2 additions just until blended. Pour into ungreased cake pan. Bake 20 to 25 minutes until top cracks and looks dry. lace cake, still in pan, upside down on wire rack to cool 20 minutes. Run knife around edge of cake to loosen; carefully turn out onto wire rack. Cool completely.
To decorate: Just before serving, place large paper doily on top of cake. Stir confectioners' sugar through sieve evenly over doily. Carefully life doily. Serves 8.
