Orange Chiffon Cake

Impress your friends with this cake. Serve on a platter with orange curls. Sprinkle orange zest on top for extra flour.
Prepare the cake: Preheat the oven to 325 ° F. Sift together the flour, 3/4 cup sugar, baking powder, and salt. Separate the eggs. Whisk together the egg yolks, butter, juice, zest and vanilla. Whisk the butter mixture with the flour mixture.Whisk the whites until foamy. Add the tartar; beat until smooth. Whisk with 3/4 cup sugar, 1 tbsp. l. Beat one at a time until peaks form. Add 1/4 of the whites to the batter; add the remaining whites.Bake in an ungreased 10-inch tube pan for 1 hour and 10 minutes, until the dough is clear. Flip the mold over the neck of the bottle to cool it. When it cools down, run a knife around the edges to remove the cake. Place on a wire rack.Prepare the icing: Mix the juice with the sugar; pour over the top of the cake and along the sides.