Great speedy comfort food. You can replace the jam with golden syrup, chocolate spread, bananas, pear slices etc. the possibilities are endless!
Cream the butter and sugar together in a bowl.
Add the egg a little at a time (I add a teaspoon of the flour too to prevent curdling) and beat well.
Add the flour and mix well.
Grease a microwaveable bowl with a little butter and dollop the jam in the bottom.
Spoon the mixture on top and cover with cling film.
Cook in the microwave for 6-8 mins. Remove the cling film (very carefully) and serve with custard.