Take the required quantity of dark chocolate into a microwave-safe bowl and microwave for 1 minute. Stir until it becomes smooth. Put parchment paper over the baking tray or a plate. After coating the walnuts with chocolate, place them on a baking sheet lined with parchment paper to cool. Once you have completed all the dipping, keep it in the freezer for around 20 minutes to cool. The dark chocolate walnut cake are ready to enjoy.