Rinse the urad dal thoroughly, soak it in water and refrigerate for about 2.5-3 hours.
Drain the soaked urad dal and grind it with a green chilly into a smooth batter using very little water or ice cubes. The batter should be thick and fluffy. You can use a wet grinder or a high-powered blender for this.
When using a blender to grind the batter for Medu Vada, it's good to incorporate some air into the batter. This helps in making the vadas light and fluffy.
After grinding the urad dal into a smooth batter, transfer it to a mixing bowl.
Using a spoon or your hands, beat the batter vigorously for a couple of minutes. This whipping action helps incorporate air into the batter, making it lighter.
You can also use a hand or electric whisk to beat the batter if you find it more convenient.
Do a small test by dropping a small amount of batter into a bowl of water. If the batter floats, it's usually an indication that it's ready for frying.
Add finely chopped onions, ginger, curry leaves, asafoetida, and salt to the batter. Mix well.
Heat oil in a deep frying pan or a kadai over medium heat.
Wet your hands, take a small amount of batter, and shape it into a round disc with a hole in the centre, forming a donut shape. (Read notes for more techniques)
Maintaining the right oil temperature is important when frying vadas. If the oil is too hot, the outside can indeed brown quickly while the inside remains undercooked. Tip to test: Drop a very small ball of batter into the hot oil, it should sizzle and brown gradually rather than immediately turning dark.
Gently slide the shaped vada into the hot oil. Fry until they turn golden brown on both sides. Make sure to cook them evenly by flipping them occasionally. Avoid overcrowding the pan with vadas.
Once the vadas are golden brown and crispy, use a slotted spoon to remove them from the oil. Place them on a plate lined with paper towels to absorb any excess oil.
Serve the Medu Vadas hot with coconut chutney or sambar.
Enjoy your homemade Medu Vadas! They are commonly served as a breakfast item or snack in South Indian households.