In a bowl whisk margarine and sugar till it becomes light and fluffy

Add in vanilla essence,then eggs one at a time till

Add in flour alternating with the juice while folding in with a spatula on the same direction

Add in the the orange zest and fold in

Pour the butter to the baking tin then bake. When you insert a knife and it comes out clean, remove from the oven and place on the wire rack then allow it cool.