Preheat oven to 375 degrees F or 180 degrees C for 10 minutes

Grease 9-inch cake pan (I used bundt cake pan) with vegetable oil

Take a mixing bowl, add all purpose flour, baking powder, salt and orange zest, and mix lightly.

Add sugar, egg yolks, vanilla essence, vegetable oil and orange juice, beat until the mixture is well combined and smooth.

Take 4 egg whites in a bowl and beat egg whites until foamy,

Add cream of tartar or lemon juice and mix until soft peak forms.

Now add this egg whites mixture into the cake batter slowly into two batches.

With a rubber spatula or wire whisk fold the egg whites with the cake batter until well blended.

Do not overmix otherwise the cake will be hard.

Pour the cake batter into the cake pan and fill the pans about ⅔ full.

Bake for 40 minutes until a toothpick inserted comes out clean.

Baking times vary from oven to oven, so keep checking after 30 minutes.

Remove from oven, turn the cake onto a plate, pour chocolate sauce from the top and sprinkle some powdered sugar through the strainer if you want to decorate it, otherwise leave this step, slice the cake and enjoy!