1Preheat oven to 325 degrees F (165 degrees C). Grease and flour one 9 inch round pan.
2Separate the eggs while cold, then bring to room temperature.
3Beat egg yolks, sugar and grated orange rind until light and fluffy. Mix flour and baking powder together. Alternately add flour mixture and orange juice to the egg yolk mixture.
4In a separate large CLEAN bowl, with a CLEAN whisk or beaters, beat egg whites to stiff peaks, and fold into batter.
5Pour batter into prepared pan and bake at 325 degrees F (165 degrees C) for 50 to 60 minutes.