Pre-heat the oven to 375 and spray a mini-muffin pan with non-stick spray. (If you are making regular sized muffins, heat the oven to 400 degrees)
In a large bowl, combine the wet ingredients. (applesauce, mashed banana, egg, milk, vanilla extract)
In a separate bowl, combine the dry ingredients. (flour, oats, brown sugar, baking powder, cinnamon, nutmeg, salt)
Slowly incorporate the dry ingredients into the bowl with the wet ingredients. I like to add the dry mixture to the wet in a few batches, stirring in-between each until everything is combined.
Add in the raisins and stir just until they are incorporated throughout the batter.
Spoon the batter into the greased muffin pan. Each cup should take about a heaping tablespoon of batter.
Bake for 10-11 minutes or until a toothpick inserted in the center of a muffin comes out clean. (if making regular sized muffins, bake for 15-16 minutes.)
Let cool in the pan then remove and store in an airtight container for no longer than 5 days.