1. Crack the egg into a bowl and whisk until frothy.
2. Add the mashed bananas, corn flour, cooked tapioca, and baking powder to the bowl, mixing thoroughly.
3. Gradually pour in the milk or water, stirring until the mixture is smooth.
4. Pour the batter into a greased pan with a center hole.
5. Cover the pan with aluminum foil or a lid and place on the stove over medium heat.
6. After 30 minutes, remove the cake from the mold, transfer it to an oven-safe pan, and bake for an additional 10 minutes to achieve a firmer texture.

Nutritional Notes: This cake leverages natural sweetness from bananas and offers gluten-free ingredients, making it ideal for health-conscious eaters or those with dietary restrictions. It provides potassium, dietary fiber, and moderate protein.