Preheat oven to 350°F (175°C). Grease an 8-inch round cake pan or line with parchment paper.
In a large mixing bowl, whisk together flour, cocoa powder, baking powder, baking soda, and salt.
In a separate bowl, combine mashed bananas, applesauce, melted coconut oil, vanilla extract, and water or non-dairy milk.
Add the wet ingredients to the dry ingredients and stir until just combined. Do not overmix.
Pour batter into the prepared cake pan and smooth the top with a spatula.
Bake for 25-30 minutes or until a toothpick inserted in the center of the cake comes out clean.
Let the cake cool completely in the pan, then remove and serve as desired. Enjoy!