Preheat your oven to 350°F (175°C). Grease a 4x8-inch (9x5-inch works too) loaf pan.
In a mixing bowl, mash the ripe bananas until smooth.
Stir the melted coconut oil or vegetable oil into the mashed bananas and vanilla extract.
Prepare the flax egg by mixing 1 tablespoon of ground flaxseed with 3 tablespoons of water. Let it sit for a few minutes to thicken.
Add the flax egg to the wet mixture and mix well.
In a separate bowl, whisk together the flour, baking soda, and a pinch of salt.
Gradually add the dry ingredients to the wet mixture and stir until the batter is just combined. Be careful not to overmix; a few lumps are okay.
Pour the batter into the greased loaf pan.
Bake in the preheated oven for about 60-65 minutes or until a toothpick or skewer inserted into the center comes out clean. Baking times can vary, so start checking for doneness around 55 minutes.
Once done, remove the banana bread from the oven and let it cool in the pan for about 10 minutes.
Afterward, transfer the banana bread to a wire rack to cool completely. Slice, serve, and enjoy your plant-based (vegan) banana bread!