Trim the prosciutto to fit each piece of veal or turkey and place it over the meat. Lay a sage leaf on top. Roll-up the escalopes and secure with a toothpick.
Heat the oil in a frying pan and cook the onions for 3-4 minutes. Add the veal or turkey rolls to the pan and cook for 5 minutes until brown all over.
Pour the wine and stock into the pan and leave to simmer for 15 minutes if using turkey, and 20 minutes if using veal. Remove the meat from the pan and serve.
