Instructions

• Preheat the oven to 325°F (165°C). Line cookie sheets with parchment paper.
• In a bowl sift together 2 cups all-purpose flour, 1/2 teaspoon baking soda, and 1/2 teaspoon salt; set aside. If baking at high altitude, add 2 tablespoons of flour to this mixture.
• In a medium bowl, combine 3/4 cup unsalted butter (melted and slightly cooled), 1 cup packed brown sugar, and 1/2 cup white sugar; mix until well blended.
• Beat in 1 tablespoon vanilla extract, 1 egg, and 1 egg yolk until the mixture is light and slightly thickened.
• Gradually add the sifted dry ingredients to the wet ingredients and mix until just combined; avoid overmixing.
• Stir in 2 cups semisweet chocolate chips by hand with a wooden spoon.
• If the dough is very wet because the butter was still hot, let it rest at room temperature for a few minutes or chill in the refrigerator until firm enough to scoop.
• Portion the dough: for big cookies, form 1/4-cup balls; for small cookies, form 1 1/2-tablespoon balls. Shape each portion into a tall mound (taller than wide) and place on the prepared cookie sheets, leaving space between cookies for spreading.
• Bake, reversing the position of the cookie sheets halfway through baking, until the outer edges are light golden brown and the centers are still soft and puffy — about 11–14 minutes for 1/4-cup cookies or 8–10 minutes for 1 1/2-tablespoon cookies. Do not overbake; the cookies will continue to cook as they cool.
• Let the cookies cool on the baking sheets until they are firm enough to lift without breaking, then transfer them to a wire rack to cool completely.