Preheat your oven to 350°F (175°C). Grease and flour a 9x5 inch loaf pan, or line with parchment paper leaving an overhang on the sides for easy removal.

In a medium bowl, combine 1/2 cup all-purpose flour, 1/4 cup granulated sugar, 1/4 cup packed light brown sugar, and 1 tsp ground cinnamon. Whisk until well combined.

Add 4 tbsp cold, cubed unsalted butter to the dry ingredients. Using your fingers or a pastry blender, cut the butter into the mixture until coarse crumbs form. Set aside.

In a large bowl, whisk together 1 3/4 cups all-purpose flour, 1 tsp baking soda, and 1/2 tsp salt. Set aside.

In another medium bowl, combine 1/2 cup granulated sugar and 1/4 cup packed light brown sugar. Pour in 1/2 cup melted and slightly cooled unsalted butter, and whisk until smooth.

Whisk in the 2 large eggs, one at a time, until fully incorporated. Stir in 1 tsp vanilla extract.

Add the mashed very ripe bananas to the wet ingredients and mix until just combined.

Pour the wet banana mixture into the dry ingredients. Using a rubber spatula, mix until just combined. Be careful not to overmix; a few lumps are fine.

Pour the banana bread batter evenly into the prepared loaf pan.

Evenly sprinkle the reserved cinnamon crunch topping over the top of the batter.

Bake for 55-65 minutes, or until a wooden skewer or toothpick inserted into the center of the loaf comes out clean. If the topping starts to brown too quickly, you can loosely tent the loaf with aluminum foil.

Once baked, remove the loaf pan from the oven and let it cool in the pan for 10-15 minutes before carefully transferring it to a wire rack to cool completely. Slicing while warm is tempting but can make it crumbly.