1. Preheat oven to 375 degrees and line a pan with 12 cupcake liners.
2. In a blender combine greek yogurt, oil, banana, vanilla extract and spinach until smooth.
3. In a large bowl add flour, sugar, baking powder, baking soda, cinnamon and salt. Whisk together and then add liquid ingredients. Stir just until combined, don't over mix.
4. Divide evenly among muffin pan and bake for 15-20 minutes or until an inserted toothpick comes out clean.