Banana Blueberry Muffins

Preheat your oven to 350°F (175°C). Line a muffin tin with paper liners or grease it lightly.
In a mixing bowl, mash the ripe bananas with a fork until they are mostly smooth. If your bananas are not as ripe, you can microwave the banana for 30 seconds before mashing.
Add the coconut oil, brown sugar, egg, and vanilla extract to the mashed bananas. Stir until the mixture is well combined.
In a separate bowl, whisk together the all-purpose flour, baking powder, ground cinnamon, and salt.
Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix; a few lumps are okay. Stir in blueberries. (If frozen, do not thaw.)
Divide the batter evenly among the muffin cups, filling each about ⅔ full. For extra tall muffins, fill the muffin cups to the rim (but this will make 9 muffins instead of 12).
Bake in the preheated oven for 18-22 minutes until muffins bounce back when gently touched.
Remove the muffins from the oven and allow them to cool in the muffin tin for a few minutes before transferring them to a wire rack to cool completely.