Begin by rinsing 1 cup of fresh blueberries under cool water, gently patting them dry with a paper towel. Set aside to allow excess moisture to evaporate.

In a blender, combine the prepared blueberries with 2 tablespoons of sugar-free blueberry syrup. Blend on high for about 30 seconds until smooth. Strain the mixture through a fine-mesh sieve into a bowl to separate the skins.

Pour the strained mixture back into the blender and add 1/2 cup of heavy cream. Blend on low speed until fully incorporated.

Take a tall glass and fill it with ice cubes, then pour one-third of the creamy blueberry mixture into the glass.

Top each glass with sparkling water, pouring slowly to maintain the bubbles.

Garnish with whole blueberries and a sprig of fresh mint. Serve immediately.