For boiled puddings, the mold or pudding basin (a vitreous china bowl with a rim) must be perfectly dry and well coated with butter. The pudding mixture must completely fill the basin. A scalded and floured dish towel or other cloth should be tied securely over the top of the basin and under the rim. The two ends of the towel should then be tied in a knot so it can be used as a handle for removing the basin from the water. For a boiled pudding that does not require a mold, the floured cloth should be tied rather loosely. The water must be boiling rapidly when the pudding is put in it and the pudding must be completely covered with water. As the water boils away, it must be replenished with more boiling water. The pudding must stand for a few minutes before being turned out of the cloth or basin so that some steam escapes and the pudding shrinks. It will then be less apt to break.
For steamed puddings, the mold or basin must also be perfectly dry and well coated with butter. The pudding mixture should only fill three-quarters of the basin. A sheet of cooking parchment, made waterproof by being rubbed with butter, or a piece of buttered foil, should be tied over the top of the pudding and under the rim. The basin should stand in a pan of boiling water which comes to just under the rim. The water should be replenished when the level goes below half the depth of the basin. Some cookery writers recommend sitting the basin on an upturned saucer. I tried this, also a trivet or nothing as a pedestal. All methods worked equally well.
Boiled and steamed puddings are served sliced with a sauce and often flaming with brandy.
While puddings are normally cooked in china pudding basins, tinned pudding molds with clamp-on lids avoid the necessity for covering the basin with parchment or a cloth. Tinned charlotte molds, bundt pans or any container that can withstand heat is perfectly acceptable. Puddings that are cooked in metal molds must, however, be turned out and stored wrapped in cheesecloth dampened with rum, brandy or fruit juice, and then returned to the mold for the final steaming (heating). The pudding basin has two advantages other than its traditional shape. Its rim facilities securing the paper or towel over the top and the cooked pudding can be stored in the basin.
Puddings must be steamed in single recipe increments. If the boiling water bath pan is large enough, several basins of pudding can be steamed together, of course. At the British Embassy, when Christmas pudding is served sometimes to over 50 people, the puddings receive their first steaming in the smaller basins and for the final steaming are turned out of the basins and placed into a larger bowl (any mixing bowl will do if it's heat-resistant china), and encouraged by some gentle patting to come together. The bowl is then covered and steamed for another few hours in the usual way, and a splendid large pudding is carried in triumphantly in a blazing glory.