Melt chocolate and butter in a double boiler. If you don't have a double boiler, you can just place the bowl of chocolate in another bigger bowl filled with hot water. Otherwise, you may also melt the chocolate in a microwave about 30 seconds.
Once melted, remove from heat and leave for a couple of minutes to cool before stirring in the cornflakes. This is to ensure the cornflakes stay crispy.
Make sure the cornflakes are well coated with dark chocolate.
Scoop into mini paper cups.
You may decorate it with colourful sprinkles.
Chill in the refrigerator for 15 minutes for the chocolate to set.
Once the chocolate has solidify, store in an air-tight container. These stay crisp for weeks.