Place cereal in resealable food-storage plastic bag; seal bag and crush with rolling pin or meat mallet (or crush in food processor). In large bowl, stir together crushed cereal and milk; let stand 5 minutes. Stir in remaining coffee cake ingredients except apple; beat 30 seconds with spoon. Gently stir in apple. Spread half the batter in pan; sprinkle streusel on top. Spoon remaining batter over streusel; spread to cover.