Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 9x13-inch baking dish.
Mix almond flour and coconut oil together in a bowl. Add enough water to form a thick dough. Press into the bottom of the baking dish to form a crust.
Beat eggs in a large bowl until smooth. Add soy milk, milk, maple syrup, hemp powder, cinnamon, and nutmeg; beat until combined. Stir apples, 1 1/4 cup oats, quinoa, pecans, raisins, and flax seeds into the batter.
Spread banana slices over crust. Pour batter evenly over banana slices. Sprinkle remaining 1/4 cup oats on top.
Bake in the preheated oven until cake is mostly set but retains some moisture, about 1 hour. Let cool to room temperature, about 30 minutes. Cover and chill before serving.