Line an 8-inch (23cm) round cake tin with two layers of cling film or parchment paper.
In a large bowl, combine butter, dark chocolate and milk chocolate. Place the bowl over a saucepan of simmering water. When the chocolate mixture has fully melted, take it off the heat.
Add the condensed milk to the melted chocolate and butter, stirring slowly to combine evenly.
Add the biscuits, Maltesers, crunchies, caramel bars and mini marshmallows, stirring well to mix everything together.
Pour the chocolate and biscuit mixture into the prepared cake tin, pressing down gently to ensure it sets firmly. Transfer to the fridge and let it chill for two hours.
Once set, remove from the fridge and drizzle with the milk and white chocolate and any other sweets you desire. Serve and enjoy!
This can store in an airtight container for up to one week.
