In large bowl, beat milk, oil, vanilla and egg with fork or wire whisk until well mixed. Stir in flour, 1/2 cup sugar, the baking powder, salt and 1/2 teaspoon cinnamon all at once just until flour is moistened (batter will be lumpy). Stir in apple. Divide batter evenly among muffin cups. In small bowl, mix topping ingredients; sprinkle over batter.