Apple Cinnamon Muffins

1-1/2 c all-purpose flour
¾ c sugar
1-1/2 tsp baking powder
1 tsp ground cinnamon
½ c milk
1/3 c butter, melted
1 egg, slightly beaten
1 c finely chopped apple

Heat oven to 375°F. Combine, flour, sugar, baking powder and cinnamon in medium bowl. Add all remaining ingredients. Stir just until flour is moistened.
Spoon batter into greased 12-cup muffin pan. Bake for 18 to 23 minutes or until lightly browned. Let stand 5 minutes; remove from pan.