Mix all the ingredients together and moisten with a little more rum or milk.
Part fill greased pudding basins (maybe pyrex), cover with two layers of gresed proof paper and steam for hours or pressure cook according to instructions. In my pressure coooker cook book the following table appears:
Add a little lemon juice or vinegar to the water as this stops the cooker discolouring inside. Place the basket (inverted) in the bottom to lift the bowl out of the water and cover the bowl with two layers of greaseproof paper. Cover the bowl with an ovenproof plate. Leave the lid loose to allow the steam to clear the pan.
Steam the pudding, check the water level by adding boiling water and then cook on hig pressure.
My mother used a Prestige High Dome Cooker made in Derby in the UK. If you were careful you could just get two small puddings in separated by the trivet. Now I have a large german cooker and it is easy to get more than one large pudding in.
When cool remove from the bowl and wrap in greased proof paper. Store to mature for a month or two.
To serve re-heat according to the instructions for your pressure cooker or steam for 15 - 60 minutes depending on the size and until hot. Don't be tempted to use a microwave oven to re-heat as the sugar burns very easily.
Serve with custard not forgetting washed silver coins and perhaps some brandy to ignite over the pudding.