We found a great article over at food52.com last week about substituting olive oil for butter in baking!
While you definitely can’t just do a straight swap for many recipes, brownies, cookies, and desserts that are a bit more dense are perfect for using olive oil instead of butter. We have a few recipes on our website for olive oil cakes and desserts already!
Something else to keep in mind, quoted from the food52.com article, is this:
“…extra-virgin olive oil is a significant flavor ingredient, not just a neutral fat or “healthy” substitute for another fat. Celebrate rather than try to hide the flavor by making sure it plays well with the others in your recipe.”
Unless you want a really green flavour to come through in your dessert, try sticking with a milder olive oil. Or, try one of the flavour fused/infused olive oils instead!