To begin making the Onion Vada Sambar Recipe;  we will first soak the dal for about 3 hours.

Using a strainer, strain all the excess water from the urad dal. We need to use very little water to grind the urad dal, so that you can shape them well if you are deep frying.

Next we will grind the dal, along with ginger and green chillies using a food processor or a mixer grinder into a very smooth batter. Make sure add very little water while grinding the dal to make a smooth batter. Transfer the batter to a bowl. 

Add in the chopped onions, coriander leaves into the batter. Stir well to combine the ingredients well into the vada batter.

Next we will preheat the Kuzhi Paniyaram Pan and add in a little oil into each cavity; once the pan is well heated spoon the mini onion vada mixture into each of the cavities. Cover the pan and allow it to steam until you notice that the top looks cooked. 

After a couple minutes of steaming of notice the top part of the mini onion vada looks cooked. At this point you could add a little more oil and then flip the vada so it can get cooked and crisp from both sides. This time, allow it to cook without the cover. 

Transfer the Mini Onion Vadas to a platter and continue the same process with the remaining batter.

To make the Vengaya Sambar recipe, pressure cook the toor dal along with 2 cups of water for 3 to 4 whistles and turn off the heat. Once the pressure releases naturally, open the cooking and mash the toor dal until soft. Keep aside.

Into a pressure cooker; add the tamarind water, onions, radish, carrot, sambar powder and salt. Pressure cook for 2 whistles and turn off the heat.

Add the cooker toor dal into the sambar water and bring to a brisk boil. Adjust the consistency by adding a little water if required.

In a small tadka pan, heat oil over medium heat. Add mustard seeds and red chillies and allow it to crackle. Stir in the asafoetida and curry leaves. Pour this over the simmering vengaya sambar. Check the salt and spices of the vengaya sambar and adjust to suit your taste. Once done, turn off the heat , stir in the chopped coriander leaves and serve. 

To serve the Onion Vada Sambar, place the vadas in a bowl or a platter, pour in some Vengaya Sambar and sprinkle some chopped onions and serve hot.