Begin by preheating the oven to 325. Grease 3 small (6 inch) round cake pans with oil.
In a mixing bowl, combine your mashed banana, applesauce, milk, oil, maple syrup, baking powder, baking soda, and vanilla. Then, add the flour and mix well.
Transfer the batter evenly into three cake rounds and bake them in the oven for 25 minutes or until they are completely cooked through the center.
Remove them from the cake pans and let them cool on a wire rack.
While the cakes cool, combine the coco whip, yogurt, and maple syrup to create the frosting. Let this sit in the fridge for 30 minutes to stiffen.
When you're ready to frost, spread a small amount of frosting (about the size of two quarters) on your serving dish. Place the first cake layer on top, then spread about ½ inch thick frosting over the top. Repeat with the second layer and frosting, then add the third layer and frost the top.
Frost the outside of the cake for a classic look, or leave “naked style” with exposed sides. Decorate as you wish. Serve to your sweet little one for their first birthday smash cake!