Use the Holsum to grease a pudding bowl (a Pyrex mixing bowl is fine).
If the bowl does not have a lid, have handy foil or a cloth big enough to cover the bowl. Have handy enough string to tie the cover on. If the bowl does not have handles, use the string to make a handle over the top of the bowl so you can lift it safely out of the boiling water.
Prepare a pot of boiling water big enough to hold the pudding bowl. The water should not come higher than 2,5 cm below the rim of the bowl. It only needs to come slightly higher than the level of the pudding batter inside the bowl.
Rub butter into flour.
Add sugar then jam.
Dissolve bicarb in milk.
Add to mixture and mix well.
Pour into the pudding bowl.
Tie a cloth cover onto the bowl with string.
Put the bowl into a pot of boiling water.
Steam for 2½ hours. (‘Steaming’ here means ‘keep the pot simmering’.) Top up the water as necessary.