- Portion size 24 servings
Preheat oven to 350°F (180°C).
Line 2 rimless baking sheets with parchment paper or foil; grease foil. Set aside.
In large heatproof bowl over pot of gently simmering water, cook egg whites with sugar, whisking occasionally, for about 10 minutes or until opaque. Remove from heat. With electric mixer, beat for about 7 minutes or until cool, thick and glossy. Fold in flour and vanilla; fold in chocolate.
Drop by heaping tablespoons (15 mL) onto prepared pans. Bake in top and bottom thirds of oven for 25 to 30 minutes or until light brown, rotating and switching pans halfway through. Let cool on racks. Sprinkle with icing sugar. (Make-ahead: Store in airtight container for up to 3 days.)