6 large eggs plus one additional egg whites
2&1/4 cups sifted cake flour
1&1/2 cups suferfine sugar
1/2 tsp salt
2 tbsp grated orrange zest
1 tbsp baking powder
1/2 cup veg oil
3/4 cup freshly squeeze orrange juice from (2 to 3 large or ranges )
1 tsp vanilla extract
1/2 tsp cream of tartar
Separate eggs while they are cold, place the egg yolks in one bowl and the white ( along with the extra egg white ) in another, cover with cling film bring to room temp about 30 minutes.
Preheat oven to 325F(170 C ) and have ready a 10 inch (25cm) tube pan.
In a bowl of electric mixer fitted with paddle attachment or hand mixer, place the flour,sugar(1/4 cup) baking powder,salt, orrange zest beat until combined. Make a well in the center of flour mixture and add the egg yolks, oil, orrange juice and vanilla extract, beat until smooth .scrape down the sides .
In separate bowl with whisk attachment beat egg whites until foamy,add cream of tartar and continue beat in the remaining 1/4 cup of sugar and beat until stiff peak form then whisk gently using rubber spatula and fold in three times onto the batter just until blended.
Pour batter into greased tube pan and bake for bout 55 to 60 minutes or until skewer inserted into the center comes out clean . ( when lightly press the cake will spring back ) immediately remove from the oven invert ( Turn upside dow) then place on a flat surface or bottle so it is suspended over the counter. Let the cake cool completely before removing from pan.
To remove the cake from pan, run a long metal spatula around the sides of the tube pan and center core. Invert to a greased wire rack. Dust the top with icing sugar , serve with whipped cream or fresh fruit.