To prepare cake, lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and 3/4 cup sugar, stirring with a whisk.
Place egg whites in a large bowl; beat with a mixer at high speed until foamy. Add cream of tartar and salt; beat until soft peaks form. Add 3/4 cup sugar, 2 tablespoons at a time, beating until stiff peaks form. Beat in vanilla, juice, and almond extract.
Sift 1/4 cup flour mixture over egg white mixture; fold in. Repeat with remaining flour mixture, 1/4 cup at a time.
Spoon the batter into an ungreased 10-inch tube pan, spreading evenly. Break air pockets by cutting through the batter with a knife. Bake at 325° for 55 minutes or until cake springs back when lightly touched. Invert pan; cool completely. Loosen cake from sides of pan using a narrow metal spatula. Invert the cake onto a plate.
Cut the cake horizontally into 3 layers, then spread each layer with 1 cup of softened ice cream or sorbet. Reassemble the cake, then freeze it until ready to serve.