Instructions

• Preheat the oven to 325°F. Spray a 9x13-inch baking pan with nonstick cooking spray and set aside.
• In a medium bowl, whisk together 2 1/8 cups all-purpose flour, 1/2 teaspoon sea salt, and 1/2 teaspoon baking soda. Set aside.
• Brown the butter: place 12 tablespoons unsalted butter in a small saucepan over medium-low heat. Swirl or stir occasionally and watch closely; the butter will foam, then the foam will subside and the butter will turn golden brown and smell nutty. Skim any foam from the surface, remove the pan from the heat, and pour the butter into a heatproof bowl, leaving any browned sediment in the pan. Let the butter cool until warm (not hot) before using.
• In the bowl of a stand mixer, combine the cooled browned butter with 1 cup packed brown sugar and 1/2 cup granulated sugar. Mix until the sugars are incorporated.
• Add 2 large eggs and 2 teaspoons vanilla extract to the mixer and beat until the mixture is smooth and uniform.
• With the mixer on low, slowly add the dry ingredients from step 2 and mix just until combined. Do not overmix.
• Stir in 2 cups semi-sweet chocolate chips and 3/4 cup chopped hazelnuts (skins removed) until evenly distributed.
• Spread the dough evenly into the prepared 9x13-inch pan, smoothing the top with a spatula. Sprinkle the top very lightly with sea salt.
• Bake for 25–30 minutes, or until the top is light golden brown and the edges begin to pull away from the pan.
• Cool the bars in the pan on a wire rack to room temperature. Once cooled, cut into squares and serve.