Preheat oven to180°C. Grease a 12-cup (10-inch) Bundt pan or two standard loaf pans (either 9x 13-inch pans or 8½ x 4½ inch pans for taller cakes) and set aside.
In a mediumbowl whisk together flour and baking powder. Set aside.
In a mixerbowl, whisk together eggs and sugar on high speed until pale and fluffy, about5 minutes.
On low speedand with the mixer running, add oil slowly until combined. Add orange juice,zest, and vanilla extract and keep whisking slowly until combined.
Add flourmixture and whisk just until combined. Be careful not to overmix.
Pour batterinto prepared pan/pans. Bake for 50 - 60 minutes for the bundt pan or 40 - 50minutes for the loaves or until a toothpick inserted into the centre of thecake comes out clean. If the top is browning quickly while baking, coverloosely with aluminium foil. Allow cake/cakes to cool completely on a wirerack.