Rinse and soak urad dal and fenugreek seeds for 2 to 3 hours. Drain the water. Now add the soaked dal to the mixer grinder along with 2 tbsp of water and grind. Sprinkle water if required to get a smooth and fluffy thick batter.
Transfer the batter in a large bowl and add the chopped spinach, onions, coriander leaves, curry leaves, green chillies, ginger, cumin seeds, hing and salt and mix everything really well. I like to beat the batter with my hands here as I feel it incorporates more air to the batter making it more fluffy and crispy.
Heat oil in a deep frying pan on medium heat.
When he oil is hot enough, drop a small portion of batter with hand or by a spoon in the hot oil. I have not made the authentic medu vada shape here, as I have made small bite sized vadas.
Fry until the vadas turn crispy and golden brown on both the sides.
Serve it hot with chutney, sambar or ketchup.