Beat cake mix, milk, oil, cream cheese and egg whites in a large bowl with electric mixer on low speed 3 minutes; beat on medium speed 2 minutes. Gently stir in blueberries. Divide batter evenly among muffin cups. Sprinkle with sugar crystals. Bake 15 to 20 minutes or until toothpick inserted in center comes out clean. Serve warm or cool. Store tightly covered at room temperature. Makes 24 muffins.