Put the lamb breasts on a board, skin side down. Mix the stuffing and spread it on the lamb. Roll and tie each breast in four places; cut to make eight rosettes. Arrange vegetables in layers in an ovenproof dish, sprinkling each layer with flour. Add rosettes and stock. Cover with foil. Cook on the centre shelf of the oven for thirty minutes at 375°F, 190°C, gas mark 5. Take off the foil and cook for further forty-five minutes. Remove the string before serving.