Add the raspberries to a blender, and blend until smooth. Press through a fine mesh strainer into a pitcher, and discard the seeds and pulp. Add the lemon juice and sparkling water, and stir to combine.
Stir in the sugar until combined. Add more to your taste, if desired.
Pour into glasses, and top with ice cubes. Serve and enjoy!
Notes
This recipe makes 2 large drinks, or 4 smaller drinks.