Step 1: Prepare the baking tin

Line a 9×9-inch square baking tin with baking paper, allowing some overhang for easy removal later.

Step 2: Melt the Mars bars, butter, and syrup

In a medium saucepan over low heat, combine the chopped Mars bars, unsalted butter, and golden syrup. Stir constantly until the mixture is melted, smooth, and well combined. Be patient to avoid burning, as the Mars bars take a little time to fully melt.

Step 3: Mix in the rice cereal

Once the Mars bar mixture is smooth, remove it from the heat. In a large mixing bowl, add the crispy rice cereal and pour over the melted mixture. Stir well to coat the cereal evenly.

Step 4: Press into the baking tin

Pour the mixture into the prepared baking tin and use a spatula to press it down firmly and evenly across the bottom. Ensure it’s compact to help the cake hold together when sliced.

Step 5: Melt the chocolate for topping

In a microwave-safe bowl, melt the milk chocolate in 20-30 second increments, stirring between each until smooth. Alternatively, melt it over a double boiler on the stovetop.

Step 6: Spread the chocolate layer

Pour the melted chocolate over the rice mixture in the baking tin and spread it evenly with a spatula or the back of a spoon. This will create a smooth chocolate topping.

Step 7: Chill and set

Place the baking tin in the refrigerator for about 1-2 hours, or until the chocolate is fully set and the mixture is firm.

Step 8: Slice and serve

Once set, remove the cake from the tin using the baking paper overhang. Cut into squares or bars and serve. Enjoy this sweet, chewy, and crispy treat!