I discovered this recipe when I was learning to make whoopie pies, which I had never heard of until I moved to North Carolina. Nothing says holidays like chocolate and peppermint!
In the bowl of a stand mixer combine the butter, sugar and golden syrup and bet until pale and creamy, approximately 10 minutes. Add the sifted flour, cocoa and baking soda and mix until a smooth dough begins to form. Scrape down the sides of the bowl and mix again. Add the chocolate and mix until combined. Cover the bowl and refrigerate for 30 minutes, or until firm.
Preheat the oven to 180 celsius (350 Fahrenheit) and take tablespoons of the dough and roll into balls and place on a baking tray lined with baking paper. Flatten the balls slightly and bake for 10 to 12 minutes or until the tops of the bookies begin to crack. Remove from the oven and leave on the tray for 2 minutes to firm up before placing on wire wracks to cool.
Once the cookies are cooled they are ready to ice. Combine the icing sugar, milk and peppermint extract in a bowl and mix until smooth. Taste the icing to see if it contains enough peppermint and adjust as necessary. The icing mixture should be fairly thick. Spread half the cookies with the icing mixture and top with the remaining cookies.