Preheat oven to 350°F (175°C). Spread nuts and seeds on a baking sheet and toast for 8–10 minutes until lightly golden and fragrant. Let cool slightly.
In a large bowl, combine toasted nuts, oats, and shredded coconut. Set aside.
In a small saucepan over medium heat, add honey, brown sugar, and butter. Stir until melted and smooth. Simmer gently for 1–2 minutes, then remove from heat.
Stir vanilla extract and fine sea salt into the warm mixture.
Pour the binder over the nut mixture and stir until evenly coated.
Line an 8x8-inch pan with parchment paper. Transfer mixture to the pan and press firmly into an even layer.
Refrigerate for 20–30 minutes to set.
Melt dark chocolate using a microwave (in 20-second intervals) or double boiler. Stir in oil if using.
Spread melted chocolate evenly over the chilled nut base.
Sprinkle flaky sea salt on top while chocolate is still warm.
Refrigerate for another 15–30 minutes until chocolate is fully set.
Lift out, slice into bars, and serve.