Cream the butter and both sugars with a paddle attachment until light and fluffy on medium speed.
Mix in the eggs and vanilla on low speed until combined.
Sift the flour, deZaan True Dark cocoa powder, salt and baking soda. Add into the batter and mix on low until just combined. Mix the rest by hand with a rubber spatula, be sure to scrape the sides and bottom.
Scoop and flatten.
Place a scoop of pistachio paste (15g) in the center of one flatten cookie dough. Top with another flattened cookie dough and pinch the edges to seal.
Shape into an even round. Chill.
When ready to bake, roll the chilled cookie dough in cocoa nibs and crushed pistachios. Sprinkle the top with sea salt. Bake at 180°C/350°F for about 6-7 minutes.