1/2 lb Butter or margarine (or a mi
          -ture of both)
 1 1/3 c  Sugar
     4    Eggs, separated
     1    Orange
 1 1/4 c  Yogurt; low fat, plain
     2 c  Flour; unbleached
     2 ts Baking powder
   1/2 ts Baking soda
   1/2 ts Salt
     1 c  Powdered sugar
 Cream butter and sugar until light and fluffy; beat in egg yolks one
 at a time. Grate zest of orange and squeeze juice. Retain 1/2
 teaspoon of zest and 1 tablespoon of juice. Add remaining zest and
 juice to creamed mixture with 1 cup of yogurt; beat well. Sift
 together flour, baking powder, baking soda and salt. Stir into
 creamed mixture, beating well. Beat egg whites until stiff. Fold into
 batter. Butter a 1 quart tube pan and flour lightly. Pour in batter.
 Bake in a preheated 350 degree oven for 45 to 50 minutes or until
 cake tester comes out clean. Cool for 10 minutes; invert on a wire
 rack. Sift powdered sugar into a small bowl. Mix with remaining zest
 juice and yogurt. Spread glaze over cooled cake and allow to harden
 slightly.
                
                 Yields       
                10 Servings                
