Where butter is sweet, milky, and often in the background of a cake’s flavor, olive oil is earthy, grassy, and bold. An olive oil cake will always have a savory edge, sometimes even a backnote of bitterness, that a butter cake will lack. Which brings us to another benefit of olive oil cakes: longevity. “I think olive oil cakes kind of get better with age,” says Elizabeth Quijada, the pastry chef at Abraço, a New York City coffee shop that is known for their olive oil cake. Olive oil cake is the only thing we're eating for breakfast now.