prepare the baking dish
Line a 20 cm x 10 cm (8-inch x 4-inch) deep baking dish with parchment paper with a few inches (or centimeters) of overhang off the sides.
make the chocolate rice mixture
Add chocolate to a small bowl and microwave in intervals until melted or place in a heat-proof bowl and melt over a pot of simmering water. When the chocolate melts, stir to combine, add the puffed rice and mix using a spatula to combine everything together. Optionally add a pinch of salt. Using a spoon, spread the mixture evenly over the prepared baking dish, then press toward the bottom of the pan.
chill and serve
Place the baking dish with the chocolate crunch bar mixture into a fridge. Leave to chill for an hour or overnight. Remove from the refrigerator, and cut into rectangles or 2 cm (1-inch) thick slices.