cream of tartar
semi-sweet chips, null, null
Preheat oven to 375℉ (190℃).
Line baking sheet with parchment paper; set aside.
In medium bowl, with electric mixer on medium speed, beat egg whites until frothy; add cream of tartar and salt.
Beat on high speed until stiff; beat in sugar 1 tablespoon at a time.
Add vanilla; fold in chocolate chips.
Drop batter by heaping teaspoonfuls onto prepared baking sheet.
Place in oven.
Turn oven off; leave cookies in oven 5 hours.
Variation: Add food coloring for festive holiday touch: green for