1. Take 500g of vegetables, you can take any vegetables like drumsticks, brinjal, lauki, Tori, kaddu, tinda, carrot, radish etc. Do not use potatoes.
2. Add 1 large diced onion and 4 green chillies.
3. Add 1/2 tbsp turmeric powder, 1 tsp chilli powder, 1 tsp salt. Add water as required, boil veggies well and remove from heat.
4. Take a lemon sized tamarind and soak it in water for 15 minutes.
5. Wash 200g of toor dal, add 3 diced medium sized tomatoes, add water as required. Cook until dal turns soft. Both veggies and dal would be cooked now.
6. Take cooked dal and mash it well, add boiled veggies. Take soaked tamarind and squeeze the pulp. Mix well. Add 2-3 glasses of water or as desired consistency.
7. Put this pan on heat and add salt to taste. Bring this to boil. Add 2 tbsp of any sambar masala or sabzi masala. You can also make your own spice mix by grinding coconut, urad dal, coriander seeds, methi, red chillies, chana dal, cumin and curry leaves together.
8. Add 1/4 tsp asifoetida/heeng. Boil for a couple of minutes. Add 1/2 cup chopped coriander leaves and boil for 1 minute.
9. Heat 1 tbsp of ghee. Add 1 tsp mustard seed and 2-3 strings of curry leaves, 2 dried red chillis. Add the sambhar when the onions turn golden brown and switch of the flame.