Add the mixed berries and lemon juice to a blender and blend until smooth.

Taste the purée and blend in simple syrup or honey as needed.

For a smoother drink, strain the purée through a fine mesh strainer (optional).

Fill a tall glass with ice cubes.

Add 2 to 3 tablespoons of berry purée to the glass.

Top with sparkling water.

Stir gently once to combine while keeping the drink fizzy.

Garnish with a few fresh berries if desired and serve immediately.