For each cocktail, you'll need:
- 1 oz elderflower liqueur like St. Germain
- 1 oz fresh grapefruit juice
- 3 oz chilled Prosecco
- Grapefruit slice for garnish
- Ice cubes
The elderflower liqueur adds a sweet, floral taste. Fresh grapefruit juice gives a tangy kick. Prosecco brings the bubbles and a light, crisp flavor.