Use two long strips of baking parchment to line a 20cm square tin. Cross them over in the middle and line them along the bottom and up the sides of the tin. Secure the overhang to the edges of the tin with foldback clips and grease the parchment.
Place the dates in a small bowl with 75ml boiling water, pushing them down to make sure they are evenly submerged. Leave for half an hour to soak.
Mix the crisped rice, cashews, pistachios, sesame seeds, chia seeds and ground flaxseed in a large bowl.
Pour the coconut oil, almond butter, vanilla extract and salt into the bowl with the soaked dates and blend using a handheld blender until smooth.
Pour the wet ingredients over the dry ingredients and stir well until everything is evenly combined.
Press the mixture into the lined tin and flatten the surface with a rubber spatula so that it is nice and even then place in the fridge for at least an hour to set.
Melt the chocolate, coconut oil and salt in a bain marie or bowl set over a saucepan of simmering water.
Pour the melted chocolate over the set cereal mixture and spread out evenly with a palette knife.
Place back in the fridge for at least an hour to set.
Remove from the fridge, sprinkle over extra sea salt and cut into bars.