
Basil syrup is a flavored sugar syrup infused with fresh basil leaves.
Basil leaves bruised into barely-warm syrup and strained rebuild it in ten minutes, roughly a handful to a cup. Mint syrup keeps the fresh green register and swaps the herb outright.
Basil cordial
Acid added to the same infusion, usually citric, and it sweetens and sharpens at once, so pour it in place of the syrup and cut the lemon back.
Basil liqueur
Alcoholic and dry: it carries the herb and none of the sugar, so the sweetness has to be built back.
A week refrigerated, and the clock runs on the color, not the flavor: basil oxidizes to olive long before it stops tasting of basil.