Grease and line a 20cm X 30cm rectangular slice tin with baking paper and set aside.
Place the sweetened condensed milk, chocolate melts and butter into a microwave-safe bowl. Melt in the microwave on 50% power in 30 second bursts until melted and smooth (approximately 3 minutes).
Stir through the crushed biscuits and coco-pops and pour the mixture into the prepared tin.
Decorate the top with the Maltesers and place into the fridge to set.
Thermomix Method
Grease and line a 20cm X 30cm rectangular slice tin with baking paper and set aside.
Place the sweetened condensed milk, chocolate melts and butter into the Thermomix bowl. Melt for 4 minutes, 60 degrees, Speed 2 (or until completely melted).
Add the crushed biscuits and coco-pops and mix on Reverse, Speed 3, 10 seconds (or until combined).
Pour the mixture into the prepared tin. Decorate the top with the Maltesers and place into the fridge to set.
Video
Notes
I used Arnott's scotch finger biscuits in this recipe. They are available from all Australian supermarkets. If you're outside of Australia, you can substitute with any plain sweet biscuit (cookies if you're in the US). Coco-pops are a brand of chocolate puffed rice made by Kelloggs. You can substitute with any brand of chocolate puffed rice you like - or even just use plain rice bubbles/puffed rice. Maltesers are a type of malted milk ball covered in chocolate - similar to Whoppers in the US.