Be sure to have clean hands before you start!
Preheat oven to 375 degrees
Measure out all dry ingredients (flour, sugar, baking powder, baking soda) in a large bowl.
Mash bananas on a plate with a fork.
In a small bowl, mix together egg, oil, vanilla and yogurt. Add banana and stir.
Add wet ingredients to dry ingredients. Add chocolate chips and gently mix (don’t over mix because muffins will be too tough).
Put muffin papers in muffin tin.
Put ¼ cup of muffin batter into muffin papers.
Bake for approximately 15 minutes or until toothpick inserted comes out clean.