Equipment and preparation: You will need a well-buttered, 1.5 litre/2½ pint capacity pudding basin and a steamer.
For the pastry, first sift the flour and the salt into a large mixing bowl. Add some freshly ground black pepper, then add the suet and mix it into the flour using the blade of a knife. When it's evenly blended, add a few drops of cold water and start to mix with the knife, using curving movements and turning the mixture around. The aim is to bring it together as a dough, so keep adding drops of water until it begins to get really claggy and sticky. Now abandon the knife, go in with your hands and bring it all together until you have a nice smooth elastic dough, which leaves the bowl clean. It's worth noting that suet pastry always needs more water than other types, so if it is still a bit dry just go on adding a few drops at a time.
After that, take a quarter of the dough for the lid, then roll the rest out fairly thickly. What you need is a circle, about 32.5cm/13in in diameter. Now line the bowl with the pastry, pressing it well all around. Next chop the steak and kidney into fairly small cubes (reserving the trimmings for the gravy), toss them in the seasoned flour, then add them to the pastry-lined basin with the slices of onion. Add enough cold water to reach almost the top of the meat and sprinkle in a few drops of Worcestershire sauce and another seasoning of salt and pepper.
Roll out the pastry lid, dampen its edges and put it in position on the pudding. Seal well and cover with a double sheet of foil, pleated in the centre to allow room for expansion while cooking. Now secure it with string, making a little handle so that you can lift it out of the hot steamer. Then place it in a steamer over boiling water. Steam for five hours, topping up the boiling water halfway through.
For the gravy, simply place the meat trimmings in a saucepan with the half onion, cover with one pint of water, add some seasoning and simmer for approximately one hour. Then strain the stock, and in the same pan, fry the remaining onion, chopped small, in the beef dripping until soft and blackened at the edges. Then stir in the flour, gradually add the stock little by little to make a smooth gravy, adding a spot of gravy browning if it's needed. Taste to check the seasoning and add a few drops of Worcestershire sauce.
To serve, either serve the pudding by spooning portions straight out of the bowl, or slide a palette knife round the edge and turn the whole thing out on to a serving plate (which is more fun!).