What you need:
- 30ml of espresso or 100ml of cold brew concentrate (try this recipe!)
- 200ml of sparkling water (add or reduce according to your taste)
- Simple sugar syrup
- Flavouring (Hazelnut, Vanilla, Caramel)
In a chilled glass, mix the coffee, syrup, and flavouring together with ice. Then pour the sparkling water into the glass. Add a squeeze of lemon to taste, and top it with cream if you prefer.