Step 1.
- Chill a champagne flute in the freezer or by filling it with ice water.
Step 2.
- In a shaker, combine elderflower liqueur and fresh lemon juice.
Step 3.
- Add ice and shake gently to chill the mixture.
Step 4.
- Strain the mixture into the chilled champagne flute.
Step 5.
- Top with sparkling wine, filling to the rim.
Step 6.
- Garnish with a sprig of fresh rosemary.