To make the crumble topping, in a medium bowl, place flour, quick oats, coconut sugar, and cold butter cut into cubes. Work with your fingertips quickly to make the crumbly sand-looking dough. Refrigerate.

Heat oven to 300 degrees F/150 degrees C. Mix flour with baking powder and pumpkin pie spice in a medium mixing bowl, sift and set aside. Butter and flour four porcelain mini loaf pans (9 oz. each).

To make the batter, pour grapeseed oil, add coconut sugar to a large mixing bowl, and mix with a rubber spatula. Add eggs, one by one, to the wet ingredients mixing between each addition. Next, add dry ingredients and delicately mix with the spatula. Mash bananas with a fork or a spoon and fold mashed banana and pumpkin puree into the principal preparation. Add maple syrup and mix with a spatula just to combine (don't over mix).

Divide batter evenly into the prepared mini loaf pans. Sprinkle the chilled streusel topping over the batter. Bake the bread on the center rack of the preheated oven for 50 to 60 minutes. Use a toothpick (a wooden pick) for doneness: if it is inserted into the center of the loaf comes out clean, it is ready. Or use a cooking thermometer to check the bread's doneness. The internal temperature of the bread should be between 200 and 205 degrees F (93 and 96 degrees C).

Take the baking pans from the oven, place them on a wire rack and cool for 10 minutes.  Then remove the bread loaves from the tins by running a butter knife around the sides of the pans. Transfer the baked bread to a cooling rack and let them cool down completely before slicing or wrapping them.