Can you use extra virgin olive oil for muffins?

It depends on what type of muffins you're baking. Extra virgin olive oil is the most flavorful of olive oils, being the product of the first pressing of the olives; therefore, it has a very distinct, olive-like flavor. So, if you're making sweet muffins, it would be better to use canola or vegetable oil. Those oils don't really have much flavor, and won't affect the taste. But, if you're making muffins that are heartier (using bran or granola or nuts, and very little, if any, sugar/fruit), then olive oil may be an interesting flavor to add.