4 tablespoons fresh lime juice, plus lime wedges for serving
2 cups diced honeydew melon or cantaloupe, cut into 1-inch cubes
2 cups diced cucumber, cut into 1-inch cubes
2 tablespoons extra-virgin olive oil
2 tablespoons snipped chives
Handful of small basil leaves
Handful of small mint leaves
Pinch of crushed red pepper (optional)
Pinch of flaky salt such as Maldon or fleur de sel (optional)
Put 5 cups of diced watermelon in a food processor or blender and blitz to a purée. Strain purée through a fine-meshed sieve into a bowl. You should have about 4 cups purée.
Season with salt and pepper and cayenne, 1 tablespoon vinegar and 2 tablespoons lime juice. Taste and adjust seasoning. Chill bowl on ice or refrigerate.
To serve, place remaining diced watermelon, honeydew melon and cucumber in a small mixing bowl. Toss with a little salt and pepper, 2 tablespoons lime juice and 2 tablespoons olive oil. Divide mixture evenly into chilled soup bowls.
Ladle watermelon purée into each bowl. Sprinkle with chives, basil and mint. Add a sprinkle of crushed red pepper and flaky salt if desired. Pass lime wedges separately.