Using an electric mixer, beat butter on high speed until you have a bowl full of little butter crumbles.
Mix in flour until completely combined with the butter. You'll now have slightly larger crumbles.
Mix in the salt and baking soda.
Mix in the sugar, brown sugar, and hard-boiled egg whites. Don't expect to see the egg whites disappear. You'll be able to see them until the cookies bake.
Mix in the vanilla extract and milk.
Fold in the chocolate chips.
Roll dough into small balls (or big ones if you like bigger cookies) and place on a cookie sheet lined with parchment or a Silpat.
Bake for 20 minutes or until the bottoms are slightly browned.