My favourite cocktail. Was running low on yellow chartreuse so substituted it out for green chartreuse. I can firmly say that this isn't a swap I'll be trying again.

Part way through making this I realised I'd run out of lemons. Works very well with lime too (for anyone else in a similar situation).

Might be a silly question, but what do I use to measure 2 drops with?

The Campari overpowers the taste of everything else in this drink - not for everyone.