Take ¾ cup of coconut (fresh, grated), 5 pieces of green chilies (broken in half), 10 pieces of shallots (whole), ½ tsp of cumin seeds, and a few curry leaves in a mixer jar and grind into a coarse paste without adding any water. Transfer to a bowl and keep aside.
Take a wide kadai, add 1 tbsp of coconut oil and let it heat. Add long, thin and even sized pieces of a bowl each of yam, snake gourd, raw banana, ash gourd, beans, carrot, pumpkin, cucumber, drumstick, mango, and mix everything gently. Then add ½ tsp of turmeric powder, 1 tsp of salt and mix well.
Add ¼ cup of water, mix nicely, cover and cook the veggies for 10 minutes on a medium low flame.
After 10 minutes, add the ground coconut paste and mix everything well. Next add a cup of smoothly whisked curd and mix well. Cover and cook for 5 minutes more.
For the tempering, heat 3 tbsp of coconut oil in a tempering pan and add 1 tsp of mustard seeds, 1 tsp of cumin seeds, and ¼ tsp of asafetida (hing) first. Once the mustard seeds start splattering, add 6 pieces of shallots (optional) and a few curry leaves. Saute for a minute over a medium flame. Transfer the prepared tempering to the curry and mix well.
Your tasty and healthy homemade avial is ready to be served hot.