1Heat oven to 400°F. Place paper baking cup in each muffin cup; spray inside of paper cups with cooking spray.
2In large bowl, stir all ingredients except berries just until moistened. Fold in berries. Spoon batter evenly into muffin cups.
3Bake 15 to 16 minutes or until toothpick inserted in center comes out clean. Cool 5 minutes; remove from pan to cooling rack. Just before serving, sprinkle muffins with powdered sugar. Serve warm.