Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and line a few baking trays (or however many you own) with baking paper
Mix the butter and caster sugar together with a spoon in a large bowl until smooth and fluffy, or use an electric mixer with the paddle attachment
Add the egg and peppermint extract, and mix them in
Mix in the plain flour, cocoa powder and baking powder
Fold in the chocolate chips
Spoon blobs of the mixture onto your lined baking trays, you can roll them between your palms for a neater appearance. Make sure to leave space between the cookies as they will spread
Bake the cookies for 12-14 minutes, leave them on the tray for 10 minutes before carefully removing and placing on racks to cool fully
Once the cookies are fully cool, lay out a piece of baking paper on the worktop. Dip half of each cookie into the melted dark chocolate and place on the baking paper
Sprinkle some crushed candy cane on the chocolate while it is still wet so it sticks, then leave the chocolate to set
Store in an airtight container and eat within 3 days. They can also be frozen