preheat the oven to 180° (gas mark 4)
beat the eggs and sugar together until smooth
add vanilla extract and oil together in the mix, keep mixing until light yellow colour
eventually, add the bicarbonate of soda into the mix (make sure to mix well!)
sift the flour into the mix and continue mixing until smooth once again
melt the butter on a saucepan, then add into the batter
juice and zest the orange, adding it into the mix
using extra amounts of butter, oil the loaf tin, along with dusting it with flour afterwards
pour the mix into the tin and put in the oven!