Preheat your oven to 350°F (175°C) and grease a 12-cup muffin tin, or line it with muffin liners.
In a large mixing bowl, combine the old-fashioned oats, flour, baking powder, baking soda, cinnamon, and salt. Stir these ingredients together to ensure they’re evenly distributed.
1 cup Oats, 1 &1/2 cup Flour, 1 tsp. Baking Powder, 1/2 tsp. Baking Soda, 1 tsp Cinnamon, 1/4 tsp. Salt
On a plate or in a small bowl, mash the ripe bananas with a fork or potato masher until smooth.
2 Ripe Bananas
In a separate bowl, add the mashed bananas along with the maple syrup, milk, oil, and vanilla extract. Stir everything together until the wet ingredients are well combined.
1 large Egg, 2 Ripe Bananas, 1/4 cup Maple Syrup, 1/4 cup Milk, 2 tsp. Vanilla Extract
Take your frozen blueberries and gently toss them in the dry ingredients. This step helps prevent the blueberries from sinking to the bottom of the muffins as they bake, ensuring that they are evenly distributed throughout each muffin.
3/4 cup Frozen Blueberries
Pour the wet banana mixture into the bowl of dry ingredients. Use a spatula or wooden spoon to fold the ingredients together until just combined. Be careful not to overmix the batter, as this can lead to dense muffins. A few lumps are perfectly fine!
Evenly distribute the muffin batter into the prepared muffin tin, filling each cup nearly to the top. If you like, you can sprinkle a little sugar on top of each muffin for a sweet, crunchy finish once they bake.
Place the muffin tin in the preheated oven and bake for 18 to 22 minutes, or until a toothpick inserted into the center of a muffin comes out clean or with just a few crumbs.
Allow the muffins to cool in the tin for 5-10 minutes before transferring them to a wire rack to cool completely. This helps them set and makes them easier to remove without breaking apart.