Brush wonton wrappers with butter and sprinkle with sugar. Press sugar side up into ungreased miniature muffin cups. Bake at 350° for 8-10 minutes or until lightly browned. Cool completely.
Place 1/2 cup raspberries in a small bowl; mash slightly. Stir in whipped topping and yogurt. Spoon into wonton cups. Top with blueberries and remaining raspberries. Garnish with confectioners' sugar and mint if desired.