Begin by preparing your glass. Brush the rim of a highball glass with agave syrup, then dip it into a small plate of salt to coat evenly. Set the glass aside.

In a cocktail shaker, combine the vodka, elderflower liqueur, grapefruit juice, lime juice, and simple syrup.

Shake the mixture vigorously to blend the flavors and chill the ingredients.

Strain the mixture into the prepared glass filled with fresh ice.

Top the cocktail with sparkling grapefruit to add a fizzy, refreshing finish.

Garnish with a rolled grapefruit wheel and a sprig of mint for a refreshing touch.