Take 1 cup of soaked Urad Dal.
Add the Urad dal to a grinder. Now add the green chilli, garlic cloves, salt as per your taste and preference, ¼ tsp Hing and 2 tbsp of water.
Grind it to a fine paste like consistency.
Pour the paste into a separate bowl and add 1 tsp cumin. Mix it well for at least 1 minute.
To check if the mixture is ready for making Medu vada, take a spoon of the mixture and pour it in a bowl full of water. If the mixture comes to the surface, then it means it is perfect for making the Medu vada.
Now, apply water and start making vada out of the mixture. Make a hole in between. You can adjust the size as per your preference.
Heat 1 cup mustard oil in a kadhai/pan. Pour the vada mixture to let them fry. Flip to the other side once one side is fried well. Continue to flip and fry them well from both sides. Fry the other Vadas in the same manner.
Fry until the Medu vada gets a nice golden color.
Serve them with Sambar or normal Chutney.