Mix cereal, flour and baking powder in large bowl; stir in frozen blueberries. Beat egg in medium bowl; mix in sugar until well blended. Stir in milk and butter.
Add to cereal mixture; stir just until moistened. (Batter will be lumpy.)
Spoon batter into greased or paper-lined muffin pan, filling each cup 2/3 full.
Bake at 400F for 20 minutes or until golden brown.