Banana gives a soft and spongy texture to the appams. You can also omit banana if you want crispy appams
I have used banana puree, instead you can also use mashed banana
You can deep fry the appams too. Take the batter using a deep curved ladle and drop it in preheated oil and fry till golden brown.
You can even add grated coconut/coconut pieces to make it flavorful
If you are making it immediately add a pinch of baking soda