I made this for the first time this year after reading about this oil in Éva's blog and I'm afraid you may have to wait till next year to pick elderflowers but it'll be so worth it!
Cram as many elderflower tufts into a mason jar and fill with a cold pressed oil of you choice. I decided on extra-virgin olive oil, which has quite a strong flavour by itself. Leave for about three weeks, then drain and put into sterilsed bottles. Even the strong olive oil ended up with a delicate flowery flavour. Next year I'm going to try cold pressed sunflower and rape seed oil, too.