I have been advised by Customs in Athens that I'll need to have my meds in labeled bottles and that I'll need to bring "the recipe" for my Adderall and Ambien. I am assuming that a written prescription is what was meant by recipe. Why is this information not available on the Rick Steves website?
Because that's the rule almost everywhere.
The label on your prescription bottle has all the information they need--name of medication, dosage, your name, name of prescribing physician, etc.
And that's only if you're stopped which is unlikely.
It does:
https://www.ricksteves.com/travel-tips/packing-light/ricks-packing-list
From the link:
Medicine and vitamins
Even if you check your suitcase on the flight, always carry on essential toiletries, including any prescription medications (don’t let the time difference trick you into forgetting a dose). Keep medicine in original containers, if possible, with legible prescriptions.
I bring two prescriptions and have a photo of the prescription label stored on the iCloud in case I ever needed to refer to it, or I had to stay longer than expected and needed more. I always brought an extra week of meds, just in case, but since Covid, I bring an extra two weeks.