Preheat oven to 350°F (175°C). Spray a 9" x 9" baking dish with cooking spray and line with parchment paper.

In a medium saucepan over medium heat, melt the butter. Continue cooking, stirring occasionally, until it simmers and the milk solids turn golden brown, about 7–8 minutes. Remove from heat.

Add dark chocolate chips, almond (or vanilla) extract, and 1/2 teaspoon salt. Stir until smooth and fully melted.

Whisk in granulated sugar and brown sugar vigorously until smooth. Let cool for about 5 minutes.

Whisk in one egg until incorporated, then add the second egg and whisk for about 10 seconds until glossy.

Fold in flour and cocoa powder gently until just combined.

Coarsely chop 1 cup pistachios and fold into the batter. Spread evenly into the prepared pan.

Bake for 20–22 minutes, or until a tester inserted in the center comes out clean. Allow brownies to cool completely.

Bring a small saucepan of water to a boil. Add 1/2 cup whole pistachios, remove from heat, and soak for 1 minute. Transfer to ice water.

Rub pistachios in a clean towel to remove skins.

Pulse pistachios in a food processor until finely ground. With the motor running, slowly add 2 tablespoons water and blend until smooth paste forms.

Transfer pistachio paste to a heatproof bowl. Add white chocolate chips, heavy cream, and remaining 1/4 teaspoon salt.

Microwave in 15-second intervals, stirring between each, until melted and smooth (about 45 seconds total). Refrigerate briefly until slightly thickened but spreadable.

Spread pistachio ganache evenly over cooled brownies. Top with chopped pistachios. Slice and serve.

These Pistachio Brownies are best enjoyed once the ganache is set but still creamy.