Clean the leek and cut into rings. Cook the dumplings according to the instructions on the packet, quench and drain. Cut the sausages into oblique, bite-sized pieces.
Heat the oil in a large pan and brown the sausage pieces nicely on all sides. Just before the end of the roasting time, add the leek and dumplings, season and fry briefly. Take everything out of the pan, keep warm and deglaze the roasting with beef stock. Thicken with flour and use the remaining ingredients to make a spicy sauce. Salt and pepper again to taste.
Pour the sauce on prepared plates and then arrange the food on top. Serve sprinkled with parsley.