Preheat the oven to 400°F. Line a 12-cup muffin pan with paper liners.
In a large mixing bowl, whisk together the oats, flour, cinnamon, baking powder and baking soda.
Add applesauce, milk, brown sugar, oil and egg; mix just until dry ingredients are moist.
Divide the batter among the muffin cups, filling them most of the way.
In small bowl, combine topping ingredients. Sprinkle evenly over batter.
Bake until the muffins are lightly browned and a toothpick inserted into the center comes out clean, 20-22 minutes. Let the muffins cool 5 minutes in the pan, then remove to a rack.