Since we don't prefer raw onions, cos of the sharpness I prefer cooking the onions a bit. If you want to use raw, go for mild tasting onions like Shallot. Refer Tip 3 for more details. Heat a pan and add the onion along with salt. I do not use oil and the salt helps to bring out the moisture from the onions.
Add the chillies. See Tip 2 for more details. Once the onions are soft, remove from heat.
Now add rest of the ingredients (excluding under tempering) in a blender along with the onions.
Blend it into a fine paste adding enough water to make for a smooth, yet slightly thick chutney.
Remove and pour it in a bowl.
In the same pan, add 1 tsp Coconut oil (or any oil of your choosing). Once hot, add the mustard seeds. When it starts popping, add the asafoetida powder. Switch off the heat and then add the curry leaves.
Pour this over the chutney. Mix well, taste and season with additional salt if needed.