Preheat oven to 350 degrees. Grease a 9x5 inch loaf pan with butter or cooking spray.

In a large bowl mash the bananas until smooth. Stir in the melted (then cooled) butter, greek yogurt, eggs, sugar and vanilla extract.

Next, stir in the baking soda, salt, cinnamon and flours until just combined.

Pour batter into the prepared pan.

For the crumb topping, place the flour, oats, brown sugar and cinnamon in a medium bowl. Rub in the room temperature butter with your fingertips until crumbs form.

Pour crumb topping on top of batter.

Bake for 50-60 minutes, or until a toothpick inserted in the center comes out clean. ** NOTE! ** You may need to cover the bread with foil to prevent from burning the top about 35 minutes into baking.

Store for 2-3 days at room temperature or in your fridge for 5-7 days. We also love to freeze individual slices and pull them out as desired!