Cut the melon and cucumber into cubes. Halve the cherry tomatoes and chop the onion finely. Put everything in a mixing bowl, season with salt and pepper, add the olive oil and balsamic vinegar.
Cut the bread into pieces and fry briefly in some olive oil. Add to the salad. Leave to stand for half an hour to an hour so that all the flavours are released. Stir in some fresh basil leaves.