1. In a food processor, puree the 8 cups of coarsely chopped watermelon. Pass through a fine-mesh strainer into a medium bowl (you should have 4 cups of watermelon juice). Discard the remaining pulp.

2. Return the watermelon juice to the food processor along with the bread, olive oil, tomato juice, water, vinegar, lemon juice and cayenne. Puree until smooth and strain into a large bowl. Season to taste with salt, cover and refrigerate until well chilled, about 4 hours.

3. Divide the gazpacho among 4 shallow bowls. Garnish each bowl with about 2 tablespoons of the finely diced watermelon. Place a toasted bread round on top. Finish with a drizzle of olive oil and a light dusting of piment d'Espelette and serve.