Grease a small loaf tin (1kg) and line it neatly with baking parchment
Put the butter, dark chocolate and syrup into a medium heatproof mixing bowl and suspend over a pan of barely simmering water (ensure the water does not touch the bottom of the bowl). Stir until melted
Crack the egg into a jug, whisk briefly and stir into the chocolate batter. Remove the bowl from the heat and let cool for 15 minutes, stirring once or twice
Meanwhile break the biscuits into chunks (6-8 per biscuit) - scoop all the chunks and crumbs into a bowl
Chop the peppermint creams into pieces but leave the Aero Bubbles intact
When ready, tip the biscuit pieces into the chocolate batter and briefly stir with a large metal spoon to combine - 4 or 5 turns should be sufficient
DO NOT MIX THE PEPPERMINT CREAM CHOCOLATE OR THE AREO BUBBLES INTO THIS BATTER (sorry to shout but this is really important)
Spoon ¼ of this mix into the base of the loaf tin, ensuring the mix reaches the corners of the tin
Spread ⅓ of the peppermint cream chunks and ⅓ of the Aero Bubbles over the base and top with another ¼ of the chocolate batter. Take care to ensure that the batter reaches the corner and the layer of peppermint chocolates are covered - use the back of a small metal spoon to guide the mix into empty spaces
Repeat with another ⅓ of the peppermint creams and Aero Bubbles and top with another ¼ of chocolate batter
Spread the remaining mint chocolates on the top and cover completely with the final ¼ of the batter. Carefully level using the back of a metal spoon
Wrap the tin in clingfilm and transfer to the fridge for around 6 hours to set
When ready, carefully remove from the loaf tin, remove the parchment and cut into 10-12 slices
Store in the fridge for up to 1 week. Remove from fridge 15 minutes before serving