Heat oven to 190C/fan 170C/gas 5.
Beat butter, sugar, egg and vanilla together
with a pinch of salt until smooth. Fold in
the flour and coconut to form a dough.
On a floured surface, shape the dough
into a round, then roll to the thickness of a
£1 coin. Cut into rounds using a 6cm
cutter. Lift onto baking sheets, then bake
for 14 mins until light golden. Cool for a
few mins, then transfer to a cooling rack.
To sandwich the biscuits, lay half out on
a baking sheet, under-side up. Put ½ tsp
jam onto each one, top with a piece of
marshmallow, then bake for 2½ mins or
until just melted. Remove from oven,
then quickly top with the other biscuits,
pressing down so that the marshmallow
sticks them together and just oozes out.
Cool for 10 mins. Put the coconut and
remaining jam onto plates, dip the edges
in the jam, then roll in the coconut. Will
keep in an airtight tin for up to 3 days.