Sift flour, baking powder and salt together. Set aside.
Beat the eggs, orange zest and vanilla until it doubles in size. Add sugar, orange juice then oil and beat until it becomes creamy in texture.
Add the flour and mix on the lowest speed. Don''t mix more than 15 - 20 seconds.
Pour the mixture in a greased baking pan. Put it in a pre-heated oven at 350° and bake for 40 minutes or until the toothpick comes out clean from the cake