Brush the peach quarters with 2 tbsp of the olive oil and grind a little black pepper over. Heat a griddle pan until really hot, add the peaches, cooking for 2-3 mins on each cut side until caramelised. Set aside.
Toss the rocket in 1 tbsp of the olive oil and pile up with the cheese and prosciutto on 4 plates. Top with the peach quarters. Whisk together the remaining oil and the vinegar, spoon over the salad and serve.