Splash a puddle of Angostura bitters into a saucer and place the sugar cube in it to soak.
2
This will take a minute ot two.
3
Stir the Champagne (or sparkling wine), the Vodka and the Blue Curacao together in a container and put into the fridge to chill.
4
Place the soaked sugar cube in the bottom of the Champagne glass, pour in the mixture and add drop in the cocktail onion, which should be loose, not on a cocktail stick.
