Put into your pot around 3-4 ltr of water. Then heat it up. Wait until it's boiling. Put the Basil inside for about 15 seconds. after removing it, put it in the bowl of cold water and ice. Let it sit for 1 minute and stir it sometimes. Remove it from the water. And squeeze the water with your hands out of the blanched Basil. Cut it into smaller parts.
Either you use the hot water from the boiling process or a kettle to heat up 1 ltr of water. Pour it into the large pitcher, add the sugar and stir it until it's dissolved.
Put a part of the warm sugar syrup and the blanched Basil into the mixer. Use the highest speed for 2 minutes and blend it well.
Mix the syrup with blueberry puree, and transfer the mixture into a clean, airtight container. By following these steps, you should end up with a delicious syrup that can be used to add a sweet, fruity flavor to a variety of drinks and desserts. Enjoy!