Preheat the oven to 350 °F (180 °C). Line a 12-hole muffin pan with paper liners. Slightly oil the papers with cooking oil spray. Set aside.
In a mixing bowl, whisk oat flour, baking powder, unsweetened cocoa powder, and salt until evenly combined. Set aside.
In a blender add banana, almond milk, olive oil, maple syrup, and vanilla extract. Blend until smooth.
Pour the banana milk mixture from the blender jug in the bowl with the dry ingredients.
Stir with a rubber spatula until consistent, fold in the chocolate chips if desired and stir to evenly incorporate.
Fill each muffin cup evenly with the batter.
Bake in the center of the oven for 30-35 minutes at 350 °F (180 °C) until a pick inserted in the center of the muffins comes out clean.
Let the muffins cool down for 1 hour on a cooling rack before serving.
