Heat oven to 375°F. Grease bottom and sides of 9-inch square pan with shortening and lightly flour, or spray with baking spray with flour. In small bowl, mix streusel ingredients; set aside.
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 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.
Bake 35 to 40 minutes or until toothpick inserted in center comes out clean. Serve warm.