Preheat the oven to 350°F and prepare your baking dish by greasing it with non-stick spray and lining it with parchment paper.
In a large mixing bowl, mash the bananas until smooth.
Add cashew butter, maple syrup, oat milk, and vanilla extract. Mix until well combined.
Incorporate almond flour, coconut flour, baking powder, baking soda, and salt. Fold in the vegan chocolate chips.
Spread the batter evenly into the prepared pan and set aside.
In a small bowl, combine the ingredients for the crumb topping until crumbles form. Sprinkle evenly over the batter, gently pressing down.
Bake for 45-50 minutes until golden brown. Allow to cool completely before slicing.
Store leftovers in an airtight container in the refrigerator for up to 4-5 days.