Step 1

Preheat the oven to 350 degrees Fahrenheit (175 degrees Celsius) and grease a 9x5 inch loaf pan with butter or cooking spray.

Step 2

In a large bowl, whisk the flour, baking powder, baking soda, cinnamon, and salt to ensure the leavening agents are evenly distributed.

Step 3

In separate bowl, whisk the granulated sugar, brown sugar, eggs, oil, and vanilla extract until well combined.

Step 4

Add the wet ingredients to the dry ingredients, and stir just until combined. Use a spatula and stop mixing when no streaks of flour are visible.

Step 5

Gently stir in the mashed bananas and grated zucchini until evenly incorporated. Then, pour the batter into the loaf pan and spread it flat with a spatula.

Step 6

Bake for 55-60 minutes, or until a toothpick inserted into the center comes out clean.

Step 7

Let cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.