Prep: Preheat oven to 350°F (175°C). Grease a 1.9L loaf pan with oil or non-stick spray. Line with parchment paper for easy removal (optional but helpful).
Make flax egg: In a small bowl, mix 1 tbsp + 1 tsp flaxseed meal with 3 tbsp water. Stir and set aside for 5 minutes to thicken into a gel.
Mash bananas: In a large bowl, mash bananas with a fork until mostly smooth (small lumps are fine).
Combine wet ingredients: To the mashed bananas, add oil, brown sugar, plant milk, vanilla, aquafaba, flax egg, and optional vegan butter. Whisk until smooth and well blended.
Mix dry ingredients: In a separate medium bowl, whisk together flour, baking soda, baking powder, salt, and cinnamon.
Combine wet + dry: Pour dry ingredients into the wet mixture. Using a spatula, gently fold until *just combined*—a few flour streaks are okay. Do not overmix (this causes toughness).
Add mix-ins (if using): If adding chocolate chips and/or nuts, toss them with 1 tsp of the measured flour first (prevents sinking). Gently fold into batter until evenly distributed.
Bake: Pour batter into prepared pan and smooth the top. Bake on center rack for 50–65 minutes. Start checking at 50 minutes:- ✅ Done when: Top is golden brown, springs back when lightly pressed, and a toothpick inserted in the center comes out clean or with a few moist crumbs (no wet batter).- 🌡️ Tip: If the top browns too quickly, loosely tent with foil after 40 minutes. Cool: Let loaf cool in pan for 10 minutes. Then run a knife around edges, invert onto a wire rack, and flip right-side-up. Cool completely (1.5–2 hours) before slicing. This sets the crumb and prevents gummy texture.
💡 Pro Tip: For extra flavor depth, add a pinch of espresso powder or orange zest to the dry ingredients. For a gluten-free version, substitute flour with a 1:1 GF blend + ½ tsp xanthan gum.
