Cake:

6 large eggs separated, plus one additional egg white
2 ¼ cups cake flour
1 ½ cups white sugar
1 Tbsp. baking powered
½ tsp. salt
½ cup vegetable oil
¾ cup freshly squeezed orange juice
2 Tbsp. orange zest
1 tsp. vanilla extract
¾ tsp. cream of tarter

Separate eggs and cover with plastic wrap and bring them to room temp. Preheat oven to 325 degrees F. Have ready tube pan.

In bowl of mixer, place flour, sugar (minus 3 Tbsp.), baking power and salt. Beat until combined. Make a well in the center of the flour mixture and add the egg yolks, oil, orange juice, orange zest and vanilla. Beat about one minute until smooth.

In a separate bowl, beat eggs whites until foamy. Add cream of tartar and continue to beat until soft peaks form. Gradually beat in remaining 3 Tbsp. of sugar and beat until stiff peaks form. With a large spatula, gently fold the eggs whites into batter just until blended.

Pour batter into tube pan and bake for 55-60 minutes or until wooden skewer comes out clean. Immediately invert cake. Let cool completely before removing from pan.

Icing

1/3 cup butter, softened.
3 cups powered sugar
1 ½ Tbsp. orange zest
3 Tbsp. orange juice

Beat butter, add other ingredients. Mix.