I have tried various oils to mix with butter for years. Olive oil is my old standby but the problem with olive oil is that it is just too strong,extra virgin oil that is and the other ones do not have the benefits of extra virgin which is cold pressed. All other olive oils they use some heating which destroys several of the nutrients of olive oil that is good for us. I have been mixing grape seed oil in with the olive oil to try to cut down the strong taste. I am still experimenting with which is the best ratio but the grapeseed oil also makes it spread much easier because even when refrigerated it goes not turn solid like olive oil.