Melt chocolate, butter and golden syrup in a double boiler. Alternately, heat a stainless steel vessel with about an inch of water, bring to a boil and lower the flame completely.
Over the stainless steel vessel, place another vessel (the bottom of this vessel should not touch the water of the stainless steel vessel) such that is rests on the rim of the lower vessel.
Place the grated chocolate, butter and golden syrup in the upper vessel.
The chocolate will melt due to the steam released from the hot water. Keep stirring till most of the chocolate melts.
Turn off the flame, remove the vessel which has the melted chocolate.
Add cornflakes, a few tablespoons at a time and mix it well. Adjust cornflakes quantity based on the chocolate mixture.
Take a muffin pan or cupcake liners, add a heaped tbsp of the cornflakes chocolate mixture to the cupcake liners.
Allow to cool to room temperature.
Once the crisps cool, set in fridge for 2-3 hours. After the chocolate crisps are set, remove from fridge and serve.