Preheat your oven to 350°F (175°C). Line a 9x9 inch baking pan with parchment paper, leaving some overhang for easy removal.
In a large mixing bowl, combine the chopped hazelnuts, almonds, pumpkin seeds, shredded coconut, chia seeds, and flaxseed meal.
In a separate bowl, whisk together the melted butter, powdered erythritol, vanilla extract, and sea salt until well combined.
Pour the butter mixture over the dry ingredients and mix thoroughly, ensuring all the nuts and seeds are coated.
Transfer the mixture to the prepared baking pan, pressing it down firmly into an even layer.
Bake in the preheated oven for 20 minutes or until the edges begin to turn golden brown.
While the granola mixture is baking, melt the dark chocolate with the coconut oil in a double boiler or microwave, stirring until smooth.
Once the granola mixture is baked, remove from the oven and pour the melted chocolate over the top, spreading it evenly.
Allow the granola bars to cool completely before lifting them out of the pan using the parchment paper overhang. Place them in the refrigerator for at least an hour to set the chocolate.
Once set, cut into 10 even bars.