To begin making the Medu Vada with Onion, firstly wash and soak the urad dal for about 4 to 5 hours.After 4 to 5 hours, grind it to a paste in a mixer grinder by adding little water at a time. Mix it thoroughly with hand to allow aeration and close the lid and keep it the fridge over night.If you are in a hurry continue with the next steps. Add all the above listed ingredients and mix well.Heat oil in wok/kadhai. Wet your hands with water to make roundels of the batter place it on one of the palms and make a hole with the finger of other hand.Slowly drop it in the hot oil and cook for about a minute or two or until the edges turn golden.Slowly turn it the other side and fry until the colour changes to golden brown. Remove it and drain it on a paper towel.Serve Medu Vada with Onion with�South Indian Coconut Chutney�for a delicious breakfast.