Wash and soak the urad dal for at least 4 hours.
Drain the water from the soaked dal and then blend it in a stone grinder or food processor till a fine paste. Make it smooth and fluffy.
Do not add too much water while blending the dal. If required just sprinkle some water.
Transfer this paste to a large bowl and beat it well with your hand to create the aeration. The more you beat it with your hand, the more soft and fluffy the medu vada will be.
Next add in the black pepper corns, green chili, baking soda, chopped ginger, chopped curry leaves, grated coconut, salt and mix well.
Heat oil. Press the vada paste into a round disc, and make a small hole in the middle like a donut. You can skip making a hole too. (For easier working, dip your hand in water before taking the paste from the bowl, the vadas slips easily into the oil)
Slide the prepared discs directly into the hot oil and cook on medium heat till golden brown in color. Serve hot with some coconut chutney or sambar.