Separate eggs, place egg yolks in one bowl and egg whites in another plus the extra egg white
Preheat oven to 170°c
In bowl place sifted flour, sugar (take 1/4 cup out), baking powder, salt. add orange zest and whisk until combined
Make well in the center and add the egg yolks, oil, orange juice, and vanilla essence. Beat until smooth
In separate bowl beat egg whites and beat until soft peaks form. gradually beat the 1/4 cup sugar and beat until stiff peaks form
With rubber spatula gently fold egg whites in 3 additions until just blended. Be careful not to deflate batter
Pour batter into greased pan
Bake for 55-60 minutes or until wooden skewer or knife inserted comes out clean
Decorate as desired
Butter cream icing. Add sugar and butter to bowl. Whisk with mixer until light and fluffy. Add milk and orange food color, whisk to combine well. Decorate cake
