Peel potatoes and cut into small cubes. Place in a pan of unsalted water and bring to a simmer, cooking for 15 minutes or so until tender.
Drain and return the pan to the heat to evaporate as much of the moisture off as you can.
Mash the potatoes and then press through a fine sieve or a potato ricer, twice, so that they are very fine.
Combine the potatoes with the icing sugar, coconut, coconut oil and peppermint extract.
Place in the fridge to cool for an hour.
Roll the mixture into small balls the size of a small walnut and keep in the fridge while you melt the dark chocolate.
To melt the chocolate, break the chocolate into pieces in a small heatproof bowl. Suspend the bowl over a pan of barely simmering water and leave it to melt.
Coat the coconut/potato balls in the melted chocolate. Use a fork and a spoon to roll them in the chocolate and let the excess drip away. Place the chocolates a silicone baking mat or into small decorative paper cases. Decorate with snowflake sprinkles and leave the chocolates in a cool place to chill.
These chocolates will keep for several days in a cool place. They taste fine if kept in the fridge although they will develop condensation when brought out into room temperature.