Heat oven to 400°F. Grease bottoms only of 12 regular-size muffin cups with shortening or cooking spray, or place paper baking cup in each muffin cup. Place cereal in resealable food-storage plastic bag; seal bag and crush with rolling pin or flat side of meat mallet (or crush in food processor).
In medium bowl, beat egg, milk and oil with fork or wire whisk until well mixed; beat in bananas. Stir in cereal; let stand 5 minutes.
Stir in flour, sugar, baking powder, cinnamon, nutmeg and salt until blended. Stir in cranberries. Divide batter evenly among muffin cups.
Bake 20 to 25 minutes or until light golden brown. Immediately remove from pan to cooling rack. Serve warm.