Preheat the oven to 180C/160 Fan/Gas 4. Put the first five ingredients in a food processor and mix to form a dough. Knead into a ball, wrap in foil and chill for 30 mins.
Roll out to the thickness of a £1 coin on a surface lightly dusted with flour. Take an 8cm round cutter and squeeze slightly so that it forms an oval. Stamp out 10 biscuit ‘bodies’. Lift these onto a baking tray lined with baking paper. Re-roll the trimmings. Use a 2cm round cutter to stamp out 20 ‘feet’. Put these on another lined baking sheet.
Bake ‘bodies’ for 15 mins, and the ‘feet’ for a few minutes less. Cool on wire rack.
Lightly beat the egg white until fluffy. Beat in the icing sugar a little at a time until smooth and glossy. Colour half the icing pale pink.
Decorate biscuits with the icing, position biscuit ‘feet’ and marshmallow ‘tails’. Add sprinkles to make feet pads.