
Elderflower liqueur is a sweet, spirit-based liqueur flavored with the blossoms of the elder (Sambucus nigra).
The elderflower note is the reason it is in the recipe and nothing reproduces it, so a swap is a decision to make a different drink. Alcohol is the other half: a cordial gives the flavor and none of the strength, and the sugar has to be recounted either way.
Cordial and syrup are non-alcoholic; the liqueur runs about 20%. Swap syrup for liqueur one to one and you lose the strength and gain sweetness. Put the alcohol back with about half the measure in neutral spirit: 20 ml of a 20% liqueur carries the ethanol of roughly 10 ml of a 40% one. Then drop the sugar from the build.
Cheaper elderflower liqueurs
A cheaper bottle carries the same flower at a lower price and usually more sugar, sometimes built on flavoring rather than an infusion. Taste it before you assume the measure transfers. The floral line reads flatter and the drink sweeter, so cut the syrup by about a barspoon and taste.
The aroma is delicate and fades with time, and the liqueur can darken toward amber if kept too long. Store sealed, away from heat and light, and use within a year or so of opening.

Elderflower Mojito
White rum

Hugo Spritz
Elderflower liqueur, Dry sparkling wine

Elderflower Collins
London dry gin

French 77
Dry sparkling wine

Elderflower Champagne
Brut Champagne, London dry gin

Elderflower Cosmo
Vodka

Elderflower Spritz
White wine, Elderflower liqueur

Garden Royale
Dry sparkling wine

Calvados Spritz
Dry sparkling wine, Elderflower liqueur, Calvados

Floral Daiquiri
White rum

Grapefruit Gin Cocktail
London dry gin

La Bicyclette
London dry gin

Pear and Elderflower Martini
London dry gin

Elder Sour
Elderflower liqueur

Wah-Wah
Pisco

Gypsy No. 1
London dry gin

Mariposa
White rum

Palomino Flor
White rum

Ruby
Vodka

Naked In The Rain
Mezcal