Heat oven to 350 degrees.
Spray a 9×5 inch loaf tin with coconut oil spray.
Whisk your eggs, bananas, oil, Greek yogurt, and sugar together in a large bowl.
Sprinkle in your flour and cornstarch a little at a time and fold into mixture. Do not overmix.
For your regular banana bread you are ready to go! For the cinnamon version add your cinnamon.
Pour your mixture into your greased loaf pan.
If you are opting for the cinnamon crumble, combine your topping ingredients and spread evenly on top of your mixture.
Place in the oven on middle rack and bake for 60 min. Make sure to bake until your toothpick comes out clean or with a few crumbs.