Orange Sponge Cake

Directions

1. Place egg whites in a large bowl; let stand at room temperature for 30 minutes. Sift the flour, 1/3 cup sugar and salt together twice; set aside.
2. In another bowl, beat egg yolks on high speed for 5 minutes or until thick and lemon-colored. Gradually beat in 2/3 cup sugar. Add orange juice and zest; beat 3 minutes longer. Gradually add flour mixture and mix well.
3. Add cream of tartar to egg whites; beat on medium speed until soft peaks form. Gradually beat in remaining sugar, 1 tablespoon at a time, on high until stiff peaks form. Fold into batter.
4. Gently spoon into an ungreased 10-in. tube pan. Cut through batter with a knife to remove air pockets.
5. Bake on the lowest oven rack at 325° for 45-55 minutes or until cake springs back when lightly touched. Immediately invert pan; cool completely, about 1 hour.
6. Run a knife around sides and center tube of pan. Remove cake to a serving plate. For glaze, melt butter in a small saucepan; remove from the heat. Add confectioners’ sugar, water and vanilla; stir until smooth. Pour over cake, allowing it to drizzle down sides.