Beat margarine and sugar together until creamy and pale

Mix in the flour and baking powder

Wrap in clingfilm and chill for one hour

Preheat oven to Gas 3/325F/170C

Roll dough out on lightly floured surface to 1cm or 1/3 inch thick. Do not over handle the dough or it will get tough

Cut out with 6cm/ 2/12 inch cutter

Bake for 10 to 15 minutes until just barely brown at edges

When cool sandwich together with jam

Mix icing sugar to a thick paste with water. Spread on top of biscuits and decorate