Levain Cookie Recipe

Ingredients

• 3/4 cup unsalted butter, softened
• 3/4 cup packed dark brown sugar
• 3/4 cup sugar
• 2 teaspoons kosher salt
• 3 cold large eggs
• 3-1/2 cups all-purpose flour
• 2-1/2 teaspoons baking powder
• 1-1/2 teaspoons baking soda
• 3 cups walnut halves
• 1-1/2 cups semisweet chocolate chips
• 1-1/2 cups dark chocolate chips