Pre-heat oven to 350 degrees F.
Lay prosciutto slices out flat in a single layer on a baking tray and bake in oven for 15-20 minutes until it is crispy and golden.¬† Remove from tray and drain on paper towels (the pieces should be firm and crispy).
Slice cheeks off peaches on three sides.¬† Shave fennel using a mandolin or sharp knife so you have paper-thin crescents and drop in ice water for a minute before draining and drying on paper towels.¬† Toss peaches, mozzarella, fennel and watercress together in a large salad bowl.
Make dressing by combining balsamic vinegar and extra-virgin olive oil.¬† Whisk as you drizzle the olive oil in so it emulsifies slightly.¬† Season with salt and pepper.¬† Dress salad then top with crispy prosciutto.
Edited: July 31st, 2009