Preheat the oven to 180oC/350oF/Gas
4. Beat the butter and sugar together until light and fluffy. Thoroughly
mix in all the remaining ingredients, except the melted plain and white
chocolate.
Line some baking sheets with non-stick
baking paper. Put four small spoonfuls of the mixture on to each sheet,
spacing them well apart to allow for spreading. Flatten the biscuits and
bake for 5 minutes.
Remove the biscuits from the oven and
flatten with a wet fork, shaping them into neat rounds. Return to the
oven for about 3-4 minutes, until they are golden brown. Work in batches
if necessary.
Let them cool on the baking sheets for
2 minutes to firm up, and then transfer them to a wire rack.
When they are cold and firm, spread
plain chocolate on the undersides of half the biscuits and white
chocolate on the undersides of the rest.