Place a medium heat-proof bowl over a saucepan of simmering water. Add all three types of chocolate. Heat, stirring occasionally, until chocolate has fully melted.

Remove chocolate from heat and add vanilla extract, peanuts and cashews; stir until well coated.

Using two spoons, drop spoonfuls of chocolate-peanut mixture onto parchment paper.

Sprinkle tops of clusters with sea salt and let cool until hard. (Note: Clusters can be refrigerated to speed up cooling process.)

Store in an airtight container at room temperature.