Preheat oven to 300F. Beat egg whites in medium bowl with electric mixer on high speed until soft peaks form. Gradually add sugar, beating until stiff peaks form. Blend in vanilla.
Spoon or pipe meringue mixture into 3 (4-inch) rounds onto each of 2 parchment or foil-covered baking sheets. Use a large spoon to make a large indentation in the center of each round, building up the sides of each round as much as possible.
Bake 1 pan at a time on center oven rack for 55 min. or until dry and golden brown.
Remove from oven; cool completely on baking sheets. Carefully remove meringues from parchment.
Toss berries together; set aside.
Place chocolate in small microwaveable bowl. Microwave on HIGH 1-1/2 to 2 min. or until chocolate is completely melted, stirring after each min. Just before serving, fill meringues with the berries and whipped topping.