Triple Citrus Yellow Cake with Lemon Curd Frosting

For cake:

box moist yellow cake mix plus all ingredients on the back of the box (eggs, oil or water)

additional egg

orange oil

lemon oil

lime oil

For topping:

container Cool Whip (This is the medium size tub, check the packaging to be sure)

lemon curd, use more if you'd like a more tart flavor 

optional garnish: fresh lemon, orange or lime zest