What is the most efficient way to prepare (very small) fresh oregano leaves?
If you're using it in something long-simmering, like soup or spaghetti sauce, you can tie a bundle together (with cooking twine or unflavored dental floss) stems and all and toss it into the pot. As it cooks, most of the oregano leaves will fall off into the food and even those that don't will impart a lot of flavor into the dish. At the end, just pull out the bundle like you would bay leaves. I've never had trouble with the stems leaching bitter flavor when using this method.