Preheat the oven to 160°C/gas 3. Heat the oil in a large, heavy flameproof casserole and quickly fry the pieces of steak until they are a good brown colour. Lift out of the casserole onto a plate using a draining spoon. Add the onions to the pan, reduce the heat to moderate and fry gently for about 10 minutes until the onions are golden brown.
Sprinkle the flour over the onions, stir well and cook for 1 minute. Pour in the ale and bring to the boil, stirring to dislodge any bits stuck to the casserole.
Add the redcurrant jelly, mustard and bay leaf, then return the meat to the casserole, followed by the carrots, turnips and mushrooms. Cover and transfer to the oven. Cook for 2 hours or until the meat is very tender. (Prepare ahead up to this point, if more convenient. Keep chilled, then reheat thoroughly before adding the dumplings.)
Shortly before the end of the, 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 8 equal portions. Roll each into a ball with floured hands.
Increase the oven temperature to 180°C/gas 4. Uncover the casserole, stir and season to taste. Gently place the dumplings on the 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.
Use stewing venison instead of braising steak, and replace the turnips with chunks of swede or baby onions. * Use 200g smaller chestnut mushrooms instead of portabellos.