Chill your glass and ingredients. Pop your wine and soda in the fridge, and if you can, chill your glasses too.
Cold ingredients mean better bubbles and cleaner flavor.
Fill a large wine glass with ice. Don’t skimp—more ice keeps the drink cold without diluting it too quickly.
Add the elderflower liqueur. Pour in 1 to 1.5 ounces. Use 1 ounce for a drier spritz, 1.5 if you prefer it sweeter.
Squeeze in fresh lemon. About 1/4 ounce (a small squeeze) sharpens the flavor. You can skip this if you like it softer, but it makes a big difference.
Top with sparkling wine. Add 3 ounces of chilled Prosecco or another dry bubbly.
Pour gently to keep the fizz.
Add soda water. Finish with 1 to 2 ounces of soda water for balance and refreshment. Taste and adjust the ratio to your liking.
Give it a light stir. A quick stir with a bar spoon or straw blends everything without knocking out the bubbles.
Garnish and serve. Add a lemon wheel and a sprig of mint, or a cucumber ribbon for a cool, garden-fresh vibe. Serve immediately while it’s ice-cold and sparkling.