In a bowl, mix together flour, baking soda, cardamom powder and sugar.
Add water gradually and make a thick batter.
Cover and set aside for 10 minutes.
The sugar will dissolve and the batter will thin out. If it is too thin, add little flour and mix.
Heat oil on medium flame.
When hot enough, pour ladle full of batter in the middle. Let it rise before pouring for the next appam.
Fry until uniformly brown.
Remove from oil and serve hot or at room temperature.