Preheat oven to 400°F and grease or line a muffin tin.
Mash bananas in a bowl with a fork until there are no more lumps.
3 large, ripe bananas
Add softened butter, vanilla, and egg, and mash it all together again.
6 Tablespoons butter, at room temperature, 1 teaspoon vanilla extract, 1 large egg, at room temperature
In a separate bowl, mix together the dry ingredients of oats, flour, both sugars, baking soda, baking powder, and cinnamon.
1 cup rolled oats (plus extra for topping), 1 ¼ cups all purpose flour, ½ cup granulated sugar, 1 Tablespoon light brown sugar, packed, ½ teaspoon baking soda, 1 ½ teaspoons baking powder, ½ teaspoon cinnamon
Add wet to dry ingredients and stir just until all ingredients are combined.
Finally, gently fold in the blueberries.
1 ½ cups blueberries (plus extra for topping)
Fill each muffin cup with batter and top with extra oats and berries, if desired.
Bake for 20 minutes or until a toothpick inserted in the center comes out clean.
Let cool on a cooling rack for a few minutes before enjoying.