Instructions

• Preheat 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.
• In a small saucepan, melt 12 tablespoons unsalted butter over medium-low heat. Continue to cook, swirling or stirring occasionally, until the butter foams, then clears and turns a golden-brown color with a nutty aroma (watch carefully to avoid burning). Remove the pan from the heat, skim off and discard any foam from the surface, then pour the browned butter into a heatproof bowl, leaving any dark sediment behind in the pan. Let the browned butter cool until warm to the touch (so it is not hot).
• In the bowl of a stand mixer (or a large bowl with a hand mixer), combine the cooled browned butter with 1 cup packed brown sugar and 1/2 cup granulated sugar and mix until combined. Add 2 large eggs and 2 teaspoons vanilla extract and mix until smooth.
• With the mixer on low, slowly add the dry flour mixture and mix only until just combined. Stir in 2 cups semi-sweet chocolate chips and 3/4 cup chopped hazelnuts (skins removed) until evenly distributed.
• Pour the dough into the prepared 9x13 pan and smooth the top with a spatula. Very lightly sprinkle the surface with sea salt.
• Bake for 25–30 minutes, or until the top is light golden brown and the edges start to pull away from the pan.
• Cool the bars completely in the pan on a wire rack to room temperature. Cut into squares and serve.