Combine sugar, water, blueberries and basil leaves in a small saucepan.

Crush the blueberries with the back of a spoon.

Bring mixture to a boil and boil for 1 minute.

Remove from heat and let sit for 30 minutes, to allow the flavor to develop.

After 30 minutes, strain the mixture through a fine mesh strainer into a bowl.

Store in the refrigerator in a tightly covered container.

To make the spritzer, fill a 16oz glass with ice.

Add 3 tbsp blueberry basil simple syrup.

Fill glass with club soda and stir gently to combine.

Garnish with blueberries and a basil leaf, if desired.