Remove the calf liver from the refrigerator and bring to room temperature.
Cut the liver into equally-sized strips.
To make the sauce, peel and finely chop the shallots. Glaze with butter. Cover with apple juice and veal stock and reduce right down. Season with salt. Dissolve the cornflour in water and gradually stir in the hot sauce until it thickens.
Wash and dry the sage. Tear the sage leaves apart and fry for approx. one minute on both sides. Leave to drain on kitchen paper. Coat the liver in flour. Knock off any excess flour. Heat the oil in a large pan, add the butter and brown the liver strips all over in the foaming butter. Be carefulnot to over-cook the liver.
To serve, arrange the liver strips in the centre of pre-warmed plates. Season with salt and pepper. Pour some of the hot sauce over the liver. Garnish with fried sage and serve immediately. Can also be served with gnocchi.