Place bread cubes on a baking sheet and toast in oven 10 to 15 minutes. Remove and let cool.
Combine the bread with tomatoes, shallots and capers and let sit for about 5 minutes. Meanwhile, add olive oil and balsamic vinegar to a bowl. Season with salt and freshly ground black pepper, to taste, whisk and add to bread. Add feta and basil to the bowl. Lightly toss with wooden spoon. Plate panzanella, garnish with basil leaves and serve.