Serve this rich, moist pudding with custard or cream on any special occasion, but for Christmas choose one of the traditional butters or sauces (see footnote). To follow Grandma's tradition of adding coins to the pudding, you can clean decimal coins by boiling them and slip them in just before serving. Create slits for the coins with a thin, sharp knife.
Thoroughly grease a 10-cup pudding basin or heatproof mixing bowl with the melted butter. Line the bottom with a round of baking paper and grease the paper. Cut a round of baking paper large enough to cover the top of the basin or bowl and grease it well, too.
Put all the pudding ingredients in a very large mixing bowl and mix them thoroughly. Spoon the mixture into the prepared pudding basin or mixing bowl and smooth the surface. Cover the mixture with the greased paper, then cover the basin or bowl with heavy-duty cooking foil, pleated in the centre to allow for expansion. Using strong string, tie the foil securely in position under the rim of the bowl or basin and leave the pudding to stand in a cold place overnight.
To cook the pudding, stand it on a trivet, a small block of wood or a folded tea towel in a large saucepan and pour boiling water into the saucepan to come halfway up the side of the bowl or basin. Add some slices of lemon to prevent the saucepan from blackening during cooking, then cover and boil very gently for 9 hours. Replenish the water frequently with more boiling water. Do not use cold water as the pudding basin or bowl may crack.
Remove the pudding from the water and discard the foil. Leave to cool, then cover with fresh baking paper and foil. Store in the refrigerator for up to two months.
On Christmas Day, steam the pudding in the same way for a further 2–3 hours and then remove the basin or bowl from the saucepan. Pour the brandy, whisky or rum into a cup and stand the cup to heat in hot water.
Meanwhile, remove the foil and paper, loosen the sides of the pudding from the basin or bowl with a palette knife and turn the pudding out onto a heated serving plate. Decorate with the sprigs of holly.
Take the heated spirit to the table with the pudding. Before serving, remove the sprigs of holly, pour the spirit over the pudding and ignite. Alternatively, pour the spirit into a long-handled ladle, ignite it and, once ﬂaming, pour it over the pudding. Serve with one or more traditional accompaniments (see footnote).