Drizzle extra virgin olive oil over the sourdough and place on a hot grill pan. Toast for a few minutes on each side until golden brown and crispy. Remove from the heat and cut into squares.
Add chopped tomatoes, herbs, celery, red wine vinegar, extra virgin olive oil, olives and bocconcini to a large bowl. Add the chopped sourdough and stir all of the ingredients together. If time permits allow the salad to sit for a few minutes to allow all of the flavours to mix before serving.