Ingredients

4 large egg whites
1/3 cup granulated sugar
1 cup sifted powdered sugar
1/2 cup unsweetened cocoa
2 (1.4-oz) English toffee candy bars
(such as Skor or Heath), crushed
Cooking spray

Beat egg whites in a large bowl with a mixer at high speed until soft peaks form.
Gradually add granulated sugar, beating until soft peaks form. Beat egg whites in a large bowl with a mixer at high speed until soft peaks form. Gradually add granulated sugar, beating until soft peaks form.

Combine powdered sugar, cocoa, and crushed candy bar in a small bowl; stir well. Gently fold half of cocoa mixture into egg whites (egg whites will deflate quickly).
Gently fold in remaining cocoa mixture until smooth.
Drop mixture by rounded tablespoon onto baking sheet coated with cooking spray.

Bake at 350 for 15 minutes (cookies will be soft in center). Cool cookies in pan on wire rack 2 minutes. Remove cookies to rack; cool completely.