Put 2 or 3 cubes of the watermelon and a couple of celery pieces into your bowls or glasses. Pour the remaining ingredients into a blender. Pulse until it reaches a soup-like consistency. Taste it and add more seasoning if needed. Chill in the fridge for 2–3 hours before serving.
Traditionally, the Spanish add bread to their gazpacho, which gives it a creamy texture. Try adding a handful of soaked cashew nuts to this recipe for the same effect.