Place the remaining watermelon, tomatoes, cucumber, onion, garlic and mint leaves into a food processor or a large mixing bowl and puree to a smooth consistency.
Add 2 tbsp of sherry or wine vinegar, 2 tbsp of evoo*, 1/2 tsp of salt and blitz again.
Taste and adjust for salt and/or acidity. Do not adjust if you are planning to use feta for garnish (since it will add another salty element).
Cover and send to the fridge for at least 3 hours.
To serve:
Cut the reserved watermelon into small cubes.
Divide the gazpacho between serving plates.
Drizzle with more evoo, garnish with watermelon cubes and sprinkle over crumbled feta.
Finish off with a grind of black pepper mill.
Notes
*evoo = extra virgin olive oil
You can prepare watermelon gazpacho a day in advance and keep it in the fridge until ready to serve. Just give it a quick whisk before dividing between plates or bowls.
You can also use small cubes of fresh cucumber and/or tomatoes for garnish.