Had an unused bunch of spring onion lying in my fridge for a week now..wanted to use it for my cooking today was in no mood for Chinese.Hence went online and googled for spring onion recipes and came across this nice Sambar recipe.
The sambar came very close to what is offered in udupi restaurants.

Method

1. Chop  around 20 stalks of spring onion along with the green leaves and keep aside. Finely chop 2 tomatoes and set aside.
2. Boil 1/2 cup of toor dal and keep aside.
3. Grind 1/2 cup of coconut, 2 tsp of cumin seeds, 2 tbsp of sambar powder,  pinch of turmeric powder, 1 marble sized ball of tamarind  and 1 tsp of jaggery powder to a fine paste with water and keep aside.
4. Heat 2 tsp of oil in a pan and add 2 tsp of mustard seeds. When they splutter add pinch of asafoetida and 1 sprig of curry leaves. 
5. Add the chopped Spring Onions &  tomatoes and mix well. Cook till the onions and tomatoes are soft.
6. Now add the ground paste, toor dal and 2 cups water and let the gravy boil for 5 mins. You can adjust the jaggery and salt now.
7. Garnish with coriander and serve with steamed rice.

I guess I can just replace the spring onions with onions, add more water and get a good sambar to go with hot idlis.