1. Preheat oven to 400°.
2. Oil 2 12-hole muffin pans; set aside.
3. In a large bowl, cream together butter, eggs and sugar.
4. Reserve 3 tablespoons flour. In a medium bowl, combine remaining flour,
5. baking powder, salt and baking soda.
6. Combine apple juice and vanilla.
7. Alternately add juice and flour mixtures to creamed butter mixture. Place diced apples in a large bowl, sprinkle with reserved flour and turn gently with a large spoon until apples are lightly coated. Fold apples into batter.
8. Fill each muffin well 3/4 full and sprinkle tops with cinnamon-sugar. Fill any remaining empty wells 1/2 full with water. Bake until muffins pull away from sides of pan and turn golden brown and crumb on sides or until tester comes out clean, about 15 to 20 minutes.