• Preheat the oven to 350℉/176℃ and line a 9x9 baking pan with parchment paper and set aside. Chop the pistachios and set aside.
  2/3 cups unsalted pistachios*

Brown the butter

• In a pot over medium-high heat, add the butter. It will melt, then begin to sizzle, crackle, and foam. Continue mixing the entire time to prevent burning. After 3-5 minutes, the nutty aroma of browned butter will arrive. There will also be brown amber specks on the bottom of your pot. Transfer into a heat-safe dish to cool for 15 minutes before using.
  3/4 cups + 2 tbsp unsalted butter

For the blondies

• Combine flour, baking powder, cinnamon, cornstarch, and salt. Set aside.
  2 cups all-purpose flour, 1/2 tsp baking powder, 1 tsp cornstarch, 1/4 tsp cinnamon, 1/2 tsp salt*
• Whisk together slightly cooled brown butter, brown sugar, and white sugar. Whisk for 2-3 minutes until well combined.
  3/4 cups dark brown sugar, 1/4 cup white sugar, 3/4 cups + 2 tbsp unsalted butter
• Add in the egg, egg yolks, and vanilla. Continue whisking until well combined, scraping the bowl as needed.
  1 large egg, 2 large egg yolks, 1 tbsp vanilla
• Mix in the dry ingredients just until a soft dough forms.
• Mix in the chopped pistachios and white chocolate.
  3/4 cups white chocolate chips*, 2/3 cups unsalted pistachios*
• Transfer into the prepared pan and sprinkle extra chopped pistachios and white chocolate on top.
• Bake for 25-35 minutes or until the edges are a light brown and the middles are soft. The blondies will continue to bake as they cool. Start checking around the 20 minute mark. A toothpick inserted in the middle will come out moist with a few crumbs.