|1 1/2 fl oz||Ketel One Vodka|
|1 fl oz||Lemon juice (freshly squeezed)|
|2/3 fl oz||Sugar-free sweetener|
|2 dash||Angostura or other aromatic bitters (optional)|
|1/2 fl oz||Pasteurised egg white|
As with most sours, adding a couple of dashes aromatic bitters greatly contributes to the cocktail's flavour but this also adds trace amounts of sugar.
Adapted from the classic serve by yours truly (Simon Difford) in January 2019.
Also see Sours - history, recipes and glassware.