Deep Dark Chocolate Cookies

** Recipe from divine baking **

* Nonstick vegetable oil spray
* 1 1/2 c. bittersweet chocolate chips (about 9 ounces), divided
* 3 lg. egg whites, room temperature
* 2 1/2 c. powdered sugar, divided (might only need 2 c.)
* 1/2 c. unsweetened cocoa powder
* 1 Tbl. cornstarch
* 1/4 tsp. salt
 

Heat oven to 350. Spray 2 large baking sheets with nonstick spray. Melt 1 c. chocolate chips in glass bowl in microwave, stirring twice, about 2 min. Cool slightly.  Using electric mixer, beat whites in large bowl to soft peaks. Gradually beat in 1 c. sugar (or half of amount you're using). Continue beating until mixture resembles soft marshmallow creme. Whisk 1 c. sugar, cocoa, cornstarch, and salt in medium bowl to blend. On low speed, beat dry ingredients into meringue. Stir in lukewarm chocolate & 1/2 c. chocolate chips (dough will become very stiff).  Place 1/2 c. powdered sugar in bowl. Roll 1 rounded Tbl. dough into ball; roll in sugar, coating thickly. Place on prepared sheet. Repeat with remaining dough, spacing 2" apart. Bake until puffed and tops crack, about 10 min. Cool on sheets on rack 10 min. Transfer to rack; cool.