In a blender, combine the fresh raspberries, lemon juice, and sugar. Blend until smooth.

Strain the mixture through a fine mesh sieve into a large pitcher to remove the seeds, pressing down with a spatula to extract as much liquid as possible.

Add the sparkling water to the pitcher and stir gently to combine.

Fill glasses with ice cubes and pour the sparkling raspberry lemonade over the ice.

Garnish each glass with lemon slices and a few fresh raspberries before serving.