Title: Best ever orange sponge cake
 Categories: Cakes
      Yield: 12 Servings
 
      6    Egg whites (3/4 cup)
    1/4 ts Salt
      6 ts Orange juice; fresh
  1 3/4 c  All-purpose flour; sifted
  1 1/2 c  Granulated sugar
      1 ts Orange peel; freshly grated
      6    Egg yolks
           Confectioners sugar
 
  Note: If desired, spray tube pan or kugelhopf pan with nonstick baking
  spray before filling with batter and baking. To cool, DO NOT invert on
  bottle. Instead place pan on wire rack to cool 30 minutes. Turn cake
  out onto wire rack and cool completely. In large bowl of electric
  mixer, let egg whites warm to room temperature, about 1 hour. Measure
  flour; sift about 2 cups flour once on a sheet of waxed paper; fill
  cups lightly to overflowing; with a spatula, cut off excess to make 1
  3/4 level cups. Sift flour with salt; set aside. With electric mixer
  at medium speed, beat egg whites until foamy. Gradually, beat in 1/2
  cup of the granulated sugar, 2 tbsp at a time, beating well after
  each addition. Continue beating until stiff peaks form when beaters
  are slowly raised. Preheat oven to 350 degrees. In small bowl of
  electric mixer, with the same beaters at high speed, beat egg yolks
  until very thick and lemon colored, about 3 minutes. DO NOT UNDER
  BEAT. Gradually, beat in remaining 1 cup granulated sugar; continue
  beating until mixture is smooth. At low speed, blend flour mixture
  and orange juice alternately into egg yolk mixture, beginning and
  ending with flour and guiding batter into beaters with scraper. Add
  orange peel. With whisk or rubber spatula, using under and over
  motion, fold yolk mixture gently into whites. Pour batter into an
  ungreased (see note 1) 9 3/4 to 10" x 4 1/2" kugelhopf pan or 10 x 4"
  tube pan without removable bottom. Bake 50 to 55 minutes until cake
  springs back when pressed with finger. Invert over bottle (see note
  1); cool completely. Using an up and down motion, run spatula around
  edge of cake and tube. Invert cake and shake to release; place on
  serving plate. Sift Confectioners sugar over top of cake. To cut
  cake, use knife with serrated edge. Cut gently, going back and forth
  with sawing motion.