juice of 1/2 orange
1 1/4 c sugar
3/4 c potato starch, sifted
1 3 1/2 oz bar semisweeet chocolate, finely grated
Preheat oven to 350 degrees.
In large bowl, whip the egg yolks, 1/2 c sugar, orange juice, oil, and salt until mixture is pale in color.
In a clean bowl with clean beaters, whip egg whites until soft peaks form. Gradually add remaining sugar, beating until firm peaks form.
With a large rubber spatula, fold the egg whites into the yolk mixture. Fold in the sifted potato starch. Last, fold in the grated chocolate.
Pour batter into an ungreased tube pan . Bake for 1 hour. At the end of 1 hour, insert a toothpick into center of the cake. Toothpick should come out clean and dry. Remove cake from oven and invert onto legs of pan or over the neck of a glass soda bottle. Let cool completely before unmolding from pan. To unmold cake, run an offset spatula around cake and remove outer piece of pan. Run spatula around center tube and base and carefully ease cake off pan and place on serving plate.