1. How to make batter for Vadas: Soak the Urad dal for 2 hours. Then grind them with very little water and green chilies and ginger .Grind coarse and thick. Beat this batter with an electric beater for 10 minutes to make it light and fluffy
Here if you have more time at hand them you may leave this batter on the shelf covered for about an hour. And then beat again before frying. If not you immediately start frying them (post tempering).
Let this batter rest till you prepare the dahi/curd for the Dahi Vadas.
2. How to make the Dahi/Curd: Take thick curd in a bowl. Add sugar, coconut (optional) and cream and beat /mix with a hand Wisk. Remove all lumps .Now, add salt about ½ tsp. Add milk to match required consistency.
3. Tempering the Vadas Batter: Heat oil. Add rai seeds .Let them splutter. Add Kadi Patta and add this straight to the vadas batter. Mix gently.
4. Frying the Vadas: Now, start making vads.Heat oil in a wok/kadai. Take a scoop of batter in your hand, make a hole with your thumb to make a donut like shape .
At a medium high flame, oil should not be cold but not piping hot. Slip in the vadas in the oil carefully and fry them on both sides. Fry till golden in color and take them out.
5. Assembling the Vadas: Soak the vadas in hot water for 5 minutes. This time will increase if you have refrigerated the vadas before assembling.
Soak them till they soak a bit water n get soft. Press them between your palms to drain the water and place them in the serving dish.
6. Pour the curd over the Vadas and garnish with red chili powder and ginger juliens.Refrigerate this for 15- 20 minutes and serve.