Prepare the artichokes by peeling off enough outer leaves to reveal the heart. Using a sharp knife cut about 2/3 of the tops off the artichokes and then cut them in half, removing the fibrous interior. Cover the artichokes with cold water and squeeze in the lemon until ready to slice and serve.
Combine the olive oil with the white wine vinegar, lemon juice, parsley and salt and pepper.
Drain the artichokes and slice them into 3mm slices, layering them onto a platter. Pour over 1/2 of the dressing to cover and then top with the rocket, torn prosciutto and the shaved Parmesan drizzling over the remaining dressing.
Serve with crusty bread.