Panzanella requires stale bread. To get the right texture, either cut the cubes and leave them out overnight to become stale, or toss with 2 tablespoons olive oil and toast at 275°F for about 20 minutes or until lightly toasted. Allow to cool before using in the salad.
In a small bowl, whisk together the vinegar, olive oil, salt and pepper.
In a large bowl, combine the bread, tomatoes, cucumbers, onions and capers. Pour a bit more than half of the dressing over the salad ingredients and toss to combine. Add more dressing if desired, but don’t not enough to make the bread too soggy right away. Add the basil and cheese, gently toss to coat.
Finish the dish with bit more salt and pepper, to taste, and garnish with whole basil leaves and a sprinkling of cheese. Serve immediately, adding more vinaigrette as desired.