Preheat the oven to 350°F. Line a standard muffin tin with cupcake liners. Set aside.
In the bowl of a stand mixer or a large mixing bowl, stir together the 1 cup unsweetened applesauce, 1 egg , ½ cup vegetable oil, ½ cup brown sugar and 1 teaspoon vanilla extract.
Whisk or sift together the 2 cups flour, 1 teaspoon baking soda, 1 teaspoon ground cinnamon and ½ teaspoon coarse kosher salt. Slowly, add the dry mixture into the wet ingredients with a spatula.
In a separate bowl, prepare the crumb topping. Mix the ½ cup rolled oats (aka quick cooking oats), 2 tablespoons brown sugar and ½ teaspoon ground cinnamon, then stir in the 2 tablespoons vegetable oil.
Equally divide the muffin batter into the 12 muffin tins and top each muffin with the prepared crumb topping.
Bake the muffins for 25-28 minutes or until the tops are golden brown and a toothpick inserted comes out clean.
If you've tried this recipe, come back and let us know how you liked them in the comments or star ratings!