
Vanilla extract is an alcoholic flavoring made by steeping cured vanilla beans in a mix of alcohol and water, drawing out their aroma.
A dash to a barspoon perfumes a fizz or a flip without adding sweetness or body. It is concentrated, so too much turns the drink harsh and bitter rather than sweeter.
Vanilla bean paste
The easiest swap, in the same amount. It leaves fine black specks. It is sweetened, but in so small an amount that barely shows.
Vanilla essence
Works one for one, though the vanilla tastes flatter.
Vanilla seeds
Scrape a vanilla bean: the seeds of a third of a bean equal 5 ml of extract. Fine-strain the finished cocktail to catch the seeds.
Use a barspoon or two to taste. Cut any plain sugar syrup by the same amount.
Kept dark with the cap screwed tight, it lasts for years, because the alcohol preserves it: an old bottle is weaker, not spoiled. Imitation essence fades faster. Keep both away from heat, or the aroma escapes.