This helps them melt evenly.
In a non-stick saucepan, melt the Mars Bars, butter, and golden syrup over low heat.
Stir continuously until you have a smooth mixture.
In a large bowl, mix the rice cereal with the melted Mars Bar mixture until fully combined.
Ensure every piece of cereal is coated.
Line a 9x9 inch baking tin with parchment paper and pour the mixture in.
Press it down to ensure it's even.
Melt the milk chocolate and spread it over the cooled cake layer.
Allow it to set before cutting into squares.