Begin by preheating your oven to 400ºF. Prepare a sheet pan with parchment paper and a second sheet pan with a wire rack on top.
Cut the baguette or bread into small crouton-sized cubes. Add to a large bowl and toss with the olive oil and salt. Add more if needed. Spread the croutons onto the wire rack above the baking sheet. This will allow them to crisp on all sides.
Place the slices of prosciutto on the parchment-lined baking sheet in little rosettes. Place both sheet pans in the oven. Remove the prosciutto after 15 minutes, and the croutons after about 20 minutes. Then allow to cool for 5 minutes.
In the meantime, chop the vegetables. Sprinkle the tomatoes with a good pinch of salt, then place in a fine mesh strainer over a bowl and allow to sit and release juices while you prepare the other vegetables. You may also whisk together the dressing ingredients in a small bowl or measuring cup.
Once the croutons have cooled for 5 minutes, place them in a large bowl along with the tomatoes, cucumber, shallot, kalamata olives, and mozzarella. Drizzle with the dressing and, if you wish, some of the tomato juices. Use tongs or salad spoons to toss the salad together, and place into a serving dish.
Allow the salad to sit for 20-30 minutes at room temperature before topping with the basil and prosciutto. Serve immediately and enjoy!