Ingredients

5 cups fresh or frozen blackberries
3/4 cup sugar
2 tablespoons all-purpose flour
1 tablespoon lemon juice
1 teaspoon grated lemon peel
1 teaspoon vanilla extract
TOPPING:
1 cup all-purpose flour
1/2 teaspoon baking powder
1/2 teaspoon baking soda
2 egg whites
1/2 cup fat-free plain yogurt
2 tablespoons butter or stick margarine, melted
2 tablespoons lemon juice
1 teaspoon vanilla extract
1/2 cup reduced-fat whipped topping

Directions

In a bowl, combine the blackberries, sugar, flour, lemon juice, lemon peel and vanilla. Spoon into an 11-in. x 7-in. x 2-in. baking dish coated with nonstick cooking spray; set aside.

For topping, in a bowl, combine the flour, baking powder and baking soda. In another bowl, combine the egg whites, yogurt, butter, lemon juice and vanilla; stir into dry ingredients just until moistened. Drop by tablespoonfuls over blackberry mixture. Bake at 400 degrees F for 30 minutes or until filling is bubbly and topping is golden. Serve with whipped topping.