Preheat the oven to 160°C. Heat the oil in a large, heavy flameproof casserole dish and briefly fry the pieces of steak until they are nicely browned. Lift the meat out of the casserole dish with a slotted spoon and set aside on a plate. Add the onions to the pan, reduce the heat to medium and fry gently for about 10 minutes until golden.
Sprinkle the flour over the onions, stir well and cook for 1 minute. Pour in the beer and bring to the boil, stirring well to dislodge any bits of food stuck to the base of the dish.
Add the redcurrant jelly, mustard and bay leaf, then return the meat to the casserole dish, followed by the carrots, turnips and mushrooms. Cover and transfer to the oven. Cook for 2 hours or until the meat is very tender.
Shortly before the end of the cooking time, make the dumplings. Put the flour, a little seasoning and the parsley sprigs into a food processor. Process briefly to chop the parsley. Mix the cottage cheese with the horseradish and milk and add to the processor. Mix to make a soft dough, adding a little more milk if necessary. (Alternatively, chop the parsley, then mix everything together in a mixing bowl.) Turn the dough out onto a lightly floured work surface and divide into eight equal portions. Roll each into a ball with floured hands.
Increase the oven temperature to 180°C. Uncover the casserole dish, stir and season to taste. Gently place the dumplings on top of the meat and vegetables, but do not submerge them. Cover, return to the oven and cook for a further 20 minutes. Serve at once.