Combine the water, sugar, blueberries and lavender flowers in a medium saucepan and heat on medium heat.
Bring to a low simmer and allow to simmer for 3-5 minutes or until the sugar is dissolved and blueberries have just started to break down.
Remove from the heat and allow to cool completely.
Add the mixture to the blender and blend until smooth. Pour through a strainer.
Pour into a baking dish and put it in the freezer. Freeze for an hour and scrape the mixture to create ice crystals. Repeat this process every hour until completely frozen, about 4 hours. You can skip the scraping and freeze first and then scrape with a fork, this method creates smaller crystals.
Place a scoop or two of vanilla ice cream into a small glass and top with a few scoops of blueberry lavender granita. Enjoy immedietly!