For the blueberry basil simple syrup:

1. In a small saucepan, heat water over medium low until just before reaches boil.
2. Stir in sugar until dissolved.
3. Stir in blueberries and basil. Let come to a simmer.
4. Simmer for 5 minutes, stirring frequently.
5. Remove from heat and strain using a fine mesh sieve or cheesecloth. Discard solids.
6. Let cool to room temperature.

For the blueberry vodka lemonade:

1. In a cocktail shaker, add ice, vodka, blueberry basil simple syrup, lemon juice, and sparkling water.
2. Shake until combined.
3. Pour into an ice filled glass.
4. Optional: garnish with blueberries, lemon slice, and/or basil leaf.