In a large bowl, mix wheat flour, cardamom powder, sugar and baking soda.
Mash banana well and transfer to the bowl . Knead all the ingredients very well to make a soft fluffy dough (can add a little water if it is not fluffy and soft enough).Keep it covered aside for 2-3 hours to ferment.
Heat oil in a deep fryer. Wet palms with a little water and make balls of desired size and fry it in the pan until the external browns well.