Muddle: Add 1 sprig fresh mint and 1 to 2 Tbsp elderflower liqueur to a wine glass. Briefly muddle or stir to release the mint oils.
Assemble: Pour in ½ cup Prosecco and 2 Tbsp sparkling water. Top with ½ cup ice cubes and garnish with slices of lemon or lime and a bunch of fresh mint.
Video
Notes
Does not store well. Serve immediately after assembling. How to make a Hugo spritz without St-Germain: St-Germain is the most widely available elderflower liqueur, but it's not your only option.
Other elderflower liqueurs: Brands like Belvoir, Thatcher's, and Giffard all make elderflower liqueurs that work as direct swaps in the same quantity. The flavor varies slightly between brands but the drink stays true to the original.
Elderflower cordial: This is the non-alcoholic route and it works well. Cordial is more concentrated than liqueur, so use about half the amount, starting with one teaspoon and adjusting to taste.