Cream together butter and sugar.

Beat eggs in a cup. Then add a bit at a time into sugar and butter. (add a little bit of flour with the egg to stop the mixture from curdling)

Fold in rest of flour.

Spoon the jam or treacle into a microwaveable dish then top with mixture.

Cook in microwave for 4 minutes. When cooked turn out onto a plate and serve.

To make a chocolate sponge add cocoa powder and replace jam or treacle with chocolate spread