Preheat your oven to 180 degrees Celsius. Use a handheld electric whisk to beat the egg and sugar until pale and fluffy. Sift in the flour and add the butter. Use a large spoon to gently fold in the flour – do not be vigorous and overmix! Melt the apricot jam by blitzing it in your micro for a few seconds, add the vinegar and set aside to cool slightly. Dissolve the bicarb of soda in the milk and add it to the batter. (NB: Peek in the bottom of the cup to ensure all the bicarb is in the batter. If not, it will not rise.) Finally add in the apricot jam and vinegar mix. Stir as little as possible – like most cake mixes this pud hates to be messed with too much.
Prep an ovenproof baking dish (with lid) by spraying it with non-stick baking spray. Spoon in the mix, cover with the lid and bake for 30-40 minutes until done. Test it the way you would a cake. Simply insert a thin knife or skewer into the middle. If it comes out clean, it’s done. If batter sticks to it, it needs a few more minutes. Serve this sponge pudding warm with warm custard. I am particularly fond of the vanilla custard powder mix from Woolies, it’s the best of the bunch.