*You want your butter melted, but not hot.  It’s best when it has a milky look, not clear yellow.  Your dough will be quite loose if you use hot melted butter and you’ll need to wait for it to harden a bit before scooping your dough.  I recommend melting slowly at half power until all the pieces are almost melted and let residual heat finish melting it.  It should be just warm to the touch, not hot.

Heat oven to 350 degrees. Adjust oven rack to middle position. Mix flour, salt, and baking soda together in medium bowl; set aside.

Beat butter and sugars until thoroughly blended. Mix in egg, yolk, and vanilla. Add dry ingredients; mix until just combined. Stir in chocolate chips.

Scoop into balls* and bake until outer edges start to harden yet centers are still soft and puffy.  Baking time will depend on the size of your cookies.  I think the texture of these cookies are best when scooped large, about 3 tablespoons of dough, each, which will bake for 9-12 minutes.  Cool cookies on cookie sheets. Serve or store in airtight container.

*alternate scoop method:  This recipe as written from ATK suggests rolling 1/4 cup dough into a ball and then breaking it in half, placing the broken side facing up on the cookie sheet.  The craggly texture of the top creates a nice shape and texture to the baked cookie.  That being said, I almost always just use an extra large cookie scoop and skip the breaking part because it’s quick and easy and they still turn out amazing.