In mixer bowl, cream butter. Gradually add sugar and beat until light and fluffy. Add eggs, one at a time, beating well after each addition. Stir in applesauce. In small bowl combine oats, flour, baking powder and salt. Add to creamed mixture and stir just until moistened.
Spoon batter into greased muffin tins, filling two-thirds full. Bake in a 425° over for 15 minutes. Remove muffins from pan immediately and brush tops with melted butter. Combine sugar and cinnamon and sprinkle mixture over each muffin.