Chop the two chocolates and place 3/4 of them in a heat-proof bowl. Place the bowl in a microwave on high heat for 30 seconds, remove the bowl, and stir the chocolates vigorously with a wooden spoon. Continue heating and stirring the chocolates in 30-second intervals, switching to 15-second intervals as the chocolates start to melt, continuing to stir vigorously with a wooden spoon in between each heating. Heat only until the chocolates are just melted. Add the remaining quarter of the chocolates and stir vigorously until melted and smooth. (If the chocolate isn't completely melted, microwave it for another 5 or 10 seconds.)
Place the cornflakes in a medium bowl, pour the chocolate mixture over the cornflakes, and immediately fold them together with a rubber spatula, being careful not to break up the cornflakes. You'll want to work quickly so the chocolate doesn't harden. Fold in the cranberries.
Line a sheet pan with parchment paper. Working with 2 soup spoons, spoon 8 mounds of chocolate crisps onto the paper. Set aside at room temperature to cool completely until hardened. Peel the crisps off the paper and serve.