Great for Passover since there is no flour or leavening products.  Instead of using cream of tartar I use a tsp of lemon juice.

3 egg whites or ½ cup liquid egg whites
1 tsp lemon juice
1/2 cup sugar
¼ cup semi sweet chocolate chips

1. Preheat oven to 275 F.  Line a baking sheet with parchment paper.
2. In clean glass bowl beat egg whites with lemon juice just until foamy. Gradually add sugar beating after each addition until stiff.
3. Fold in chocolate chips.
4. Drop by tbsp onto parchment baking 1 hour until dry. Garnish with extra chocolate chips.