- 2 1/2 cups flour
- 1/2 cup dark chocolate cocoa powder
- 3/4 teaspoon kosher salt
- 1/2 teaspoons baking soda
- 2 1/2 sticks unsalted butter, room temperature
- 1 1/2 cups brown sugar
- 1 teaspoon vanilla extract
- 1 large egg
- 1 cup dark chocolate chips
- 1 cup pistachios,coarsely chopped
- In a medium bowl whisk together flour, cocoa powder, kosher salt, and baking soda. In the bowl of your stand mixer on high speed, beat butter, brown sugar, and vanilla until light and fluffy, about 4 minutes. Reducing speed to low, gradually add dry ingredients mixing just to combine. Mix in egg white. Fold in chocolate chips and chopped pistachios.
- Divide dough into 4 pieces. Shape each piece into an log about 1 1/2″ in diameter. Wrap log tightly in parchment paper and chill until firm, at least 4 hours.
- Preheat to 350°F.
- Cut logs into 1/4″–thick rounds and transfer to parchment-lined baking sheets, spacing 1/2″ apart.
- Bake cookie in preheated oven 10–12 minutes or until set around edges and centers look dry. Transfer to wire racks and let cool.
MAKE AHEAD: Cookie dough can be made 1 month ahead; freeze instead of chilling. Slice frozen logs into rounds just before baking.