Prepare a center rack in the oven. Preheat the oven to 350°F. Butter a standard loaf pan (9 x 5 inches) and line it with parchment paper.
In a small bowl, combine the ground flaxseed and warm water. Set aside to thicken for 10 minutes.
In a large bowl, place the mashed bananas. Add the melted vegan butter, yogurt, organic cane sugar, brown sugar, flaxseed mixture, and vanilla. Stir with a spatula until well combined.
Add the gluten-free baking flour, baking soda, and salt to the wet ingredients. Fold gently with a spatula until nearly just combined, being careful not to overmix.
Gently fold in ½ cup of the vegan chocolate chips, and walnuts, if using, mixing until no dry flour is seen in the mixture. Pour the vegan banana bread batter into the prepared loaf pan and place it in the center rack of the oven. Sprinkle the remaining chocolate chips on top.
Bake for 50-60 minutes until browned on top, or until a toothpick inserted in the center comes out with a few crumbs. Let it cool in the pan for 20 minutes, then transfer the loaf to a cooling rack and remove the parchment paper. Let the banana bread cool for at least 1 hour. Serve and enjoy!
Notes
Choose overripe bananas for the sweetest flavor - the skins should be completely brown.
Don't overmix the vegan banana bread batter for the best results. Gently fold with a spatula until the flour is incorporated throughout.
Use room temperature ingredients.
Any leftover banana bread can be stored in an airtight container at room temperature for up to 3 days. For longer storage, it can be kept in the refrigerator, tightly wrapped, for up to a week.
Tightly wrapped sliced banana bread can be frozen for up to 3 months. Thaw at room temperature or warm the slices in the microwave before enjoying.