Preheat oven to 375° F. Place cupcake liners into muffin pan; set aside.
In a large bowl, mix together flour, oats, baking soda, salt, and cinnamon; set aside.
Add the applesauce, sugar, and eggs to a separate bowl, and whisk until fluffy.
Mash bananas with the back of a fork then add to applesauce mixture along with the milk and vanilla; mix well.
Add the wet ingredients to the dry ingredients and stir just until combined. Fold in the blueberries.
Spoon mixture into muffin cups, filling each approximately 3/4 full.
Bake in preheated oven for 18-20 minutes or until a toothpick inserted in the center of a muffin comes out clean.