Prepare: Preheat the oven to 350 F and lightly spray a muffin pan with cooking spray or line with muffin liners.
Mash Banana: Place the banana in a mixing bowl and mash with a fork until it forms a smooth paste.
3 small slightly overripe bananas
Add Wet Ingredients: Add the brown sugar, vanilla and oil and mix until fully combined.
1/2 cup brown sugar, 2 tbsp olive oil, 1 tsp vanilla extract
Add Dry Ingredients: Add the remaining ingredients and gently mix until all of the flour is incorporated. Once the flour is mixed in, stop mixing.
1.5 cups all-purpose flour, 1 tsp baking soda, 1/2 tsp salt, 1/2 tsp cinnamon
Bake Muffins: Divide the muffin batter into 9 muffin cups in the prepared muffin tray using a spoon or ice cream scoop. Sprinkle the top of the muffins with brown sugar (optional). Bake the muffins in the preheated oven for 30 minutes until golden brown and a knife or toothpick inserted into the center of a muffin comes out clean.
Cool and Enjoy: Let the muffins sit in the pan for a few minutes then transfer to a cooling rack to finish cooling.