Line your square pan with parchment paper, leaving some overhang for easy removal.
Break the dark chocolate into small pieces and place them in a heatproof bowl.
Set the bowl over a saucepan of gently simmering water, making sure the bottom doesn’t touch the water, and melt the chocolate slowly until glossy and smooth.
While the chocolate melts, toast the cornflakes lightly in a dry skillet over low heat for about 2 minutes until fragrant—this adds a smoky aroma and enhances their crunch.
Remove the melted chocolate from heat and stir in the butter until completely melted and the mixture is smooth.
Gently fold the toasted cornflakes into the melted chocolate mixture, ensuring all the cereal is evenly coated with the glossy chocolate.
Pour the mixture into your prepared pan and use a spatula or the back of a spoon to press it down firmly and evenly, smoothing the surface.
Place the pan in the fridge and chill for at least 2 hours until the bars are set and firm.
Once firm, lift the block out of the pan using the parchment overhang and transfer to a cutting board.
Use a sharp knife dipped in hot water to cut the bars into even squares or rectangles for serving.
Serve immediately or store in an airtight container in the fridge for up to a week. Enjoy these crunchy, chocolatey treats anytime!
