Preparation Steps

• Brown the butter: In a light-colored saucepan over medium heat, melt the butter and cook, stirring, until golden brown with toasty milk solids on the bottom, 5 to 7 minutes. Transfer to a large mixing bowl and let cool 20 minutes.
• Whisk in sugars: Add light brown sugar and granulated sugar to the cooled brown butter and whisk until glossy and combined.
• Add eggs and vanilla: Whisk in eggs one at a time, then vanilla, until the mixture is smooth and slightly thickened.
• Combine dry ingredients: In a separate bowl, whisk flour, cornstarch, baking soda, and fine sea salt.
• Mix dough: Stir the dry ingredients into the wet until just combined with no dry pockets.
• Fold-ins: Gently fold in chopped pistachios and white chocolate chips (if using).
• Optional chill: Cover and chill the dough 30 to 60 minutes for thicker cookies.
• Preheat oven to 350°F. Line 2 baking sheets with parchment paper.
• Scoop and top: Scoop dough into 1.5 tablespoon portions, spacing 2 inches apart. Press a few extra pistachios on top of each ball.
• Bake 10 to 12 minutes, until edges are set and centers are slightly soft. Cool on the sheet 5 minutes, then transfer to a rack and finish with a pinch of flaky sea salt.