Step 1. Prepare the Baking Dish

Lightly grease a 9×9-inch baking dish or line it with parchment paper, allowing some overhang for easy removal once the cake has set.

Step 2. Melt the Mars Bars, Butter, and Golden Syrup

In a saucepan over low heat, add the chopped Mars bars, butter, and golden syrup. Stir continuously until the mixture is melted and smooth. Take care to keep the heat low to avoid burning the chocolate.

Step 3. Add the Rice Krispies

Remove the melted Mars bar mixture from the heat. Pour in the Rice Krispies and gently fold until they are evenly coated with the chocolate caramel mixture.

Step 4. Press into the Baking Dish

Pour the Rice Krispies mixture into the prepared baking dish. Use a spatula to press it down firmly into an even layer. Place in the fridge for about 15-20 minutes to set slightly.

Step 5. Melt the Milk Chocolate

While the base is chilling, melt the milk chocolate in a microwave-safe bowl in 20-second intervals, stirring in between, or over a double boiler until smooth.

Step 6. Pour the Chocolate Topping

Remove the baking dish from the fridge and pour the melted chocolate over the Rice Krispies base, spreading it evenly with a spatula to cover it completely.

Step 7. Chill and Serve

Place the baking dish back in the fridge for at least 1 hour, or until fully set. Once firm, remove the cake from the dish using the parchment overhang, cut it into squares, and enjoy!