Whip egg whites until fluffy. Add salt, vanilla, cream tartar. Add sugar slowly while beating. Beat until stiff. Fold in chocolate chips. Bake 250 2 hours & turn off oven. Leave in oven 3 more hours or overnight.
Cookies should be crisp and melt in your mouth. Exceptionally humid weather can cause these cookies to be a bit chewy. To encourage crispiness you can put these back into low oven (180 degrees) until crisp.
*This recipe is easily doubled. I usually double it when I make it.