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 20 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!