In a mixing bowl, mash the ripe banana until it becomes a smooth paste. Add rice flour and wheat flour (if using) to the mashed banana. Mix in milk or water to reach a smooth, pourable batter consistency.
Add jaggery if you want extra sweetness, ensuring it is well dissolved. Sprinkle in a pinch of cardamom powder and a pinch of salt, and mix everything thoroughly to make a smooth batter.
Heat a non-stick pan or dosa tawa over medium heat. Once hot, reduce the heat slightly and add a small amount of ghee or butter.
Pour a ladleful of batter onto the pan and spread it gently to form a small, thick dosa. Cook on low to medium heat until small bubbles form on the surface. Flip the dosa gently and cook the other side until golden brown.
Let the dosa cool slightly before serving it to your baby. You can serve it plain or with a little ghee spread on top.