Darkest Chocolate Cookies

• 1 1/2 cups bittersweet Guittard chocolate chips (about 9 ounces), divided
• 3 large egg whites, room temperature
• 2 1/2 cups powdered cane sugar, divided (I used 2 cups)
• 1/2 cup unsweetened dark cocoa powder
• 1 tablespoon cornstarch or arrow root
• 1/4 teaspoon sea salt

1. Preheat oven to 350°F. Spray 2 large baking sheets with nonstick spray. Melt 1 cup chocolate chips in glass bowl in microwave, stirring twice, about 2 minutes. Cool slightly.
2. Using electric mixer, beat whites in large bowl to soft peaks. Gradually beat in 1 (I halved the sugar here) cup sugar. Continue beating until mixture resembles soft marshmallow creme. Whisk 1 cup sugar, cocoa, cornstarch, and salt in medium bowl to blend. On low speed, beat dry ingredients into meringue. Stir in lukewarm chocolate and 1/2 cup chocolate chips (dough will become very stiff).
3. Place 1/2 cup sugar in bowl. Roll 1 rounded tablespoon dough into ball; roll in sugar, coating thickly. Place on prepared sheet. Repeat with remaining dough, spacing 2 inches apart. Bake until puffed and tops crack, about 10 minutes. Cool on sheets on rack 10 minutes. Transfer to rack; cool.