In a saucepan, place the blueberries and water over medium heat. Allow them to simmer for about 5 minutes or until the berries soften and release their juices, then remove from heat.

Using a fork, gently mash the blueberries into a purée.

Pour the puréed blueberries through cheesecloth into a bowl, collecting the vibrant juice.

Return the extracted juice to the saucepan and simmer over low heat until it thickens to a syrup-like consistency, approximately 10-15 minutes.

Once thickened, remove the syrup from heat and let it cool slightly. Mix the syrup with kosher salt in a bowl until the salt granules are evenly coated.

Spread the blueberry-salt mixture on a parchment-lined tray and let it dry for 24 hours in a cool, dry place.