Beat cream, 2 tablespoons of the sugar and vanilla in large bowl with electric mixer on medium speed until soft peaks form. Gently stir in mascarpone cheese. Cover. Refrigerate until ready to serve.
Mix remaining 1/3 cup sugar and cornstarch in medium saucepan. Stir in water and vinegar until well blended. Stir in blueberries. Stirring constantly, bring to boil on medium heat and boil 1 minute. Pour into medium bowl to cool slightly. Add raspberries and pepper; toss gently to coat.
Grill angel food cake slices over medium heat 45 to 60 seconds per side or until golden brown grill marks appear. To serve, spoon berry mixture over each slice of cake. Top with a dollop of whipped cream mixture.