Generously butter the inside of two 1.2 litre/2 pint pudding basins.
Spoon the jam into the base of the pudding basin and set aside.
Beat the butter, golden syrup and sugar together in a mixer until light and fluffy.
Beat in half the eggs followed by half the flour and when well combined, add the remaining eggs and flour. The mixture should be at a dropping consistency. Add a splash of milk if the mixture is too thick.
Spoon the mixture into the pudding basins, only filling them three quarters full, then smooth the surface with the back of a spoon.
Loosely cover with cling film, allowing room for the cling film to inflate as the mixture rises, and cook in the microwave for five minutes.The pudding is done when a skewer inserted into the centre of the pudding comes out clean.
Leave to stand for five minutes then run a blunt knife around the edge of the pudding to loosen the sides, carefully invert onto a deep plate and remove the basin.
To serve, spoon the extra jam over the pudding, cut into generous wedges and serve with custard.