1. Prepare Your Baking Pan and Oven: Start by preheating your oven to 350 F (175 C). Grease and flour a 9×5-inch loaf pan, or line it with parchment paper for easy removal. This prevents the bread from sticking and ensures a clean release.

2. Combine Dry Ingredients: In a medium bowl, whisk together the all-purpose flour, baking soda, salt, and ground cinnamon. Make sure there are no lumps and the spices are evenly distributed. Set this bowl aside.

3. Mix Wet Ingredients: In a large bowl, combine the melted unsalted butter, granulated sugar, and light brown sugar. Whisk until well combined and smooth. Beat in the large egg and vanilla extract until fully incorporated.

4. Add Bananas and Zucchini: Stir the mashed ripe bananas into the wet ingredient mixture. Then, gently fold in the grated zucchini that has been squeezed dry. Squeezing out excess moisture from the zucchini is crucial to prevent a soggy bread.

5. Combine Wet and Dry Mixtures: Gradually add the dry ingredient mixture to the wet ingredient mixture, stirring only until just combined. Be careful not to overmix, as overmixing can lead to a tough bread. A few streaks of flour are fine.

6. Transfer to Loaf Pan and Bake: Pour the batter into your prepared loaf pan and spread it evenly. Place the pan in the preheated oven and bake for 50-60 minutes, or until a wooden skewer or toothpick inserted into the center comes out clean. The top should be golden brown.

7. Cool Before Slicing: Once baked, remove the loaf pan from the oven and let the bread cool in the pan for about 10-15 minutes. This allows it to set up properly. Then, carefully invert the bread onto a wire rack to cool completely before slicing. Slicing warm bread can cause it to crumble.