Make a sugar syrup from the first two ingredients: Bring sugar and water to a boil in a saucepan on medium heat while stirring. Turn the heat down and cook for another minute. Remove from the stove and let cool down.
Puree the blueberries together with 2 tablespoons of sugar in the blender or in the food processor. Mix together the cooled syrup, lemon juice and blueberry puree and place in a jug. Chill in the refrigerator until ready to serve.
Add 60 to 80 ml of blueberry lemonade base per glass and fill up with ice-cold water (or sparkling mineral water). Sufficient for at least 12 glasses. Very refreshing!