Slice the chicken breasts in half horizontally into two thinner escalopes. Put between 2 sheets of plastic film and bat out thinly without tearing with a rolling pin or meat hammer. Season each with a little black pepper.
Lay 2 slices of Prosciutto Crudo flat so that they are slightly overlapping. Place a sage leaf on top of the ham. Place one of the chicken escallops on next at right angles to the ham and finally add another sage leaf then fold the whole thing up in the Prosciutto Crudo. Repeat with the rest of the chicken, sage and ham.
Heat a large frying pan then add olive oil. Add the remaining sage leaves, fry until crisp. Remove from the pan and drain on kitchen paper. Add the chicken escallops to the pan and fry until golden brown about 2mins. Turn the wrapped chicken over at this point add the butter. When it’s golden brown finish with a little lemon juice, remove the meat from pan and keep warm. Add the chicken stock and bring to the boil to create a sauce. Serve the saltimbocca on a warm plate with freshly cooked pasta and the cooking juices. Top with crispy sage leaves and a light dusting of parmesan