Finely chop raw kataifi dough into 1/2-inch strands. Melt 3 tbsp butter in a wide skillet over medium heat, add kataifi, and toast stirring continuously for 6 to 8 minutes until golden-amber and fragrant.

Transfer toasted kataifi to a medium bowl and let cool for 5 minutes. Fold in pistachio cream, tahini, and 1/4 tsp sea salt until completely coated in vibrant emerald green. Set aside.

Preheat oven to 350°F (175°C). Line an 8x8-inch metal baking pan with parchment paper, leaving an overhang on sides for easy lifting.

Melt cubed butter and chopped dark chocolate together in a heatproof bowl set over simmering water (or in microwave in 30-second bursts). Whisk in Dutch cocoa powder until glossy and smooth.

In a large bowl, vigorously whisk whole eggs, egg yolk, granulated sugar, and brown sugar with a hand mixer for 4 minutes until pale, thick, and ribbon-like. Stream in melted chocolate and vanilla.

Gently fold in all-purpose flour and salt using a rubber spatula just until no flour streaks remain. Do not overmix.

Pour half of the brownie batter into the prepared pan and smooth evenly. Spoon the crunchy pistachio knafeh filling evenly across the batter, pressing gently into a solid layer.

Dollop remaining brownie batter on top and gently spread with an offset spatula to cover the green knafeh layer.

Bake at 350°F (175°C) for 26 to 28 minutes until edges are set and a toothpick inserted in the brownie edge comes out with moist crumbs (the knafeh center will remain soft). Cool completely in pan, then chill in refrigerator for 2 hours for ultra-clean knife slices.

Melt chocolate topping with coconut oil and drizzle across brownies. Top with chopped roasted pistachios and flaky Maldon salt before slicing into 16 squares.