Toast Brazil nuts and macadamia nuts separately in a dry pan over medium heat until golden and fragrant. Allow to cool completely, then chop finely.

Create a double boiler by placing a heatproof bowl over a pot of simmering water. Add 200g of the chopped dark chocolate and melt slowly, stirring occasionally until smooth.

Remove melted chocolate from heat and whisk in coconut cream, agave nectar, vanilla extract, and sea salt until well combined.

Fold in açaí powder and half of the chopped nuts, mixing until evenly distributed. The mixture should be thick and glossy.

Transfer mixture to a lined baking dish and refrigerate for 30 minutes until firm enough to handle but still pliable.

Using a teaspoon, scoop mixture and roll into 16 uniform balls. Place on a parchment-lined tray and freeze for 15 minutes.

Melt remaining 100g chocolate. Mix cocoa powder with remaining chopped nuts in a shallow bowl. Dip each truffle in melted chocolate, then roll in cocoa-nut mixture.