Pre-heat oven to 350 and line or grease 12 muffin cups.
Mash your bananas.
Stir in sugar.
Stir in oil.
Gently add blueberries. You can coat them with a little flour to help them not sink while baking.
Combine dry ingredients, then stir into wet ingredients.
Mix until just combined.
Scoop into muffin pan.
Bake for 16-20 minutes.