Scoop out the flesh of the watermelon into a blender. Add the sugar. Pulse until smooth. You may have to do the watermelon in batches.
Transfer the liquid to a bowl. Now stir in the vodka and lime juice. Stir until it is all combined.
Add this mixture to a baking dish of about 22.9 × 33cm. Cover the dish with cling wrap very well. Please in the freezer.
Check on your granita after one hour. Once your ice is starting to form, you can scrape the ice with a fork. Put the granita back into the freezer.
Prepare yourself for the most refreshing, ice cold treat of the summer! Serve as a dairy-free dessert, a palate cleaner or even a welcome drink.
