What does Frodo find that the elves left for him the first morning of his journey with the ring?

From the text:

'They have left us fruit and drink, and bread,' said Pippin. 'Come and
have your breakfast. The bread tastes almost as good as it did last night. I
did not want to leave you any, but Sam insisted.'

When they came to make their meal, they found that the Elves had filled their bottles with a clear drink, pale golden in colour: it had the scent of a honey made of many flowers, and was wonderfully refreshing.