Preheat oven to 160 degrees celsius and line a 20cm square tin with baking paper. Set aside.
Place the butter into a microwave-safe bowl. Heat for 1 minute.
Add the caster sugar and cocoa powder and stir.
Heat in the microwave on 30 second bursts (50% power) until melted and combined - stirring each time.
Allow to cool slightly.
Add the vanilla extract and the eggs and whisk until combined.
Sift the plain flour into the bowl and mix gently.
Pour the brownie mixture into the prepared tin and bake for 30 minutes or until just cooked through (do not overcook).
Leave in the tin to cool completely.
Trim any raised edges off the brownie so you have a completely flat square brownie.
Turn the brownie over onto a flat board.
Cut the brownie into 16 equal rectangles.
Cut the pretzels in half using a sharp knife.
Press the pretzels into the top of the brownie pieces for 'antlers'.
Spread melted milk chocolate over the front of the brownie pieces (do a couple at a time so that the chocolate doesn't set too quickly).
Add a Jaffa for the nose and 2 silver cachous for the eyes.
Trim the candy canes with a knife so that you have small straight pieces (approx 6 cm in length). Insert the candy cane into the base of the brownie pieces.
Store in an airtight container at room temperature for up to 3 days.