Preparation

• Heat oven to 300°F.
• Beat egg whites and cream of tartar in large bowl with mixer on high speed 3 to 5 min. or until soft peaks form. Beat in granulated sugar, 1 Tbsp. at a time, until stiff peaks form. Combine chocolate and flour; gently stir into egg white mixture.
• Drop tablespoonfuls of egg white mixture, 1 inch apart, into 45 mounds on 2 parchment-covered baking sheets.
• Bake in top and bottom thirds of oven 24 to 26 min. or until tops are firm to the touch, rotating baking sheets after 12 min. Transfer to wire racks; cool completely. Sprinkle with powdered sugar.