Cream the butter and brown sugar together in a bowl until light and smooth. Stir in the egg with 1 tablespoon of flour, then add the remaining flour, baking powder, mixed spice and ginger until the mixture comes together as a dough. Wrap in clingfilm and chill for 30 minutes in the fridge.
Preheat oven to 180 C / Gas 4.
On a floured surface, roll out the dough to the thickness of a £1 coin. Using Easter cutters, stamp out the biscuits and place onto a baking tray.
Bake for 10 to 12 minutes, or until just golden. Transfer onto a cooling rack and leave to cool completely.
Mix the icing sugar with about 1/2 a tablespoon of water. Mix till smooth, adding more water if needed. Spoon into a piping bag and ice the biscuits with patterns of your choice. Add a few drops of food colouring if you wish. Leave to dry and eat up!
If you do not wish to ice the biscuits, they will freeze easily.