I've just revisited this recipe as the blue hue in the pic has been troubling me. I can't find notes but I suspect I added blue curaçao to accompany the orange juice so I have reformulated recipe to include blue curaçao.

I made the original blue/green-tinged drink in the photo but worryingly I've just made it three times with slightly different specs and all three are mud-coloured. I'm using Kahlua and I suspect a different coffee liqueur is needed? Wish I'd left myself better notes! If it wasn't for the photo I'd say Blue Mountain wasn't a reference to the drink's colour but to the Blue Mountains in Jamaica that are noted for coffee.