Adapted from Cook's Illustrated, January/February 1996 

Ingredients:
2 1/8 cups (2 cups plus 2 Tbs) unsifted bleached all-purpose flour
½ tsp salt
½ tsp baking soda
12 Tbs unsalted butter (1 ½ sticks), melted and cooled until warm
1 cup brown sugar
½ cup granulated sugar
1 large egg plus 1 egg yolk
2 tsp vanilla extract
¾ cup semi-sweet chocolate chips (I recommend Ghirardelli Semi-Sweet chips)*
¾ cup milk chocolate chips (I recommend Ghirardelli Milk Chocolate chips)
½ cup white chocolate chips (I recommend Ghirardelli White Chocolate chips)
Parchment paper

Heat oven to 325°F.  Adjust oven racks to upper-and lower-middle positions. 

Mix flour, salt, and baking soda together in a medium bowl, set aside.

Mix sugars, then add butter and blend thoroughly.  Mix in egg, yolk, and vanilla.  Add dry ingredients; mix until just combined.  Stir in chips.

Form scant ¼ cup dough into a ball.**  Holding the dough ball use fingertips of both hands and pull ball into two equal parts.  Rotate halves ninety degrees so the jagged surfaces are directed up.  Join the halves, again forming a single cookie.  The jagged surface should form the top of the cookie.  Do not smooth the dough’s uneven surface.  Place formed dough onto two parchment paper lined 16 x 14 inch lipless cookie sheets, about nine dough balls per sheet.

Bake 15-18 minutes (start checking at 13 minutes), reversing cookie sheet's position half way through the baking.  Bake cookies until they are golden brown, and the outer edges start to harden but the centers are still soft and puffy.  Be careful not to over bake.  Cool cookies on the cookie sheets.

*It is important to use a high quality chocolate for these cookies.  They are loaded with chocolate and using an inferior chocolate will greatly impact their taste. 

**If the dough is very soft and hard to work with, refrigerate for 10 to 20 minutes.  This dough may be refrigerated up to 2 days or frozen up to 1 month.