Preheat oven to 400º. Lightly grease a muffin tin with cooking spray, or line with paper muffin liners.
Prepare topping: In a small bowl, whisk together ¼ cup oats, 1 tablespoon brown sugar, and ⅛ teaspoon cinnamon. Add 1 tablespoon melted butter and mix together until well combined; set aside.
In a large bowl, combine the oats, flour, baking powder, baking soda, cinnamon and salt. In another bowl, whisk together the applesauce, brown sugar, milk, oil, vanilla and egg. Add to dry ingredients and mix just until moistened. Stir in raisins.
Divide batter evenly into 12 muffin cups. Use your fingers to sprinkle muffins with topping.
Bake at for 16-18 minutes or until a tester inserted into the center comes out clean. Remove from oven and cool for a few minutes in the pans.
Remove muffins from pans and cool on a wire rack.