• Begin by preheating your oven to 350°F (or 325°F for nonstick pans). Prepare an 8x8-inch pan by greasing it with cooking spray and lining it with parchment paper, allowing some to hang over the edges for easy lifting.

For the Base:

• Follow the instructions on the brownie mix package to create the brownie and cookie dough. Evenly spread the brownie mix in the bottom of your prepared pan. Drop nine small balls of cookie dough over the brownie base, arranging them in a 3-by-3 grid.
• Bake for 34 to 38 minutes. To check for doneness, insert a toothpick about 2 inches from the edge; it should come out nearly clean. Allow the bars to cool fully on a wire rack.

For the Kadayif Layer:

• In a large skillet, melt the butter over medium-high heat. Stir in the kadayif and cook for 5 to 10 minutes until it turns golden and crispy. Once done, transfer it to a bowl to cool.
• Combine the melted pistachio cream with the cooled kadayif, mixing well to ensure everything is coated and sticky. Spread this mixture over the cooled brownie bars, pressing it down gently.

For the Ganache:

• Heat the heavy cream in a small saucepan over medium-low heat until it becomes hot but does not boil. Pour this hot cream over the chopped chocolates in a heatproof bowl and let it sit for 3 to 5 minutes. Gently whisk the mixture until it is smooth and shiny.
• Use a spatula to distribute the ganache evenly over the layer of pistachio kadayif.
• To add decoration, place 1 to 2 teaspoons of melted pistachio cream in a small plastic bag, snip off a corner of the bag, and drizzle over the ganache. Use a knife or a skewer to create gentle swirls for an attractive marbled look.
• Refrigerate the brookies for at least one hour to let the ganache firm. Once set, lift the bars using the parchment overhang and slice into 9 squares (3 rows by 3) for serving. Wipe the knife clean and warm between each cut to ensure neat edges.