Wash dal. In a pressure cooker, combine dal, turmeric powder, onion and tomato along with 2-3 cups of water. Cook on medium heat till the pressure releases 4-5 times or for 20 minutes.

Take oil. Crackle mustard, cumin. Add fenugreek seeds and udad dal. Add onions and fry a bit. Add green chillies, dry red chillies, curry leaves, asafoetida powder and salt. Fry well on medium heat till the onions are golden brown and a bit crispy. Stir in between for even cooking.

Add tomatoes. Cook till they are soft. Add the powder spices. Mix and then add the veggies. Combine everything well.add water till the surface of the veggies. Cover and cook till the veggies are cooked about 80-90%.

Add cooked dal followed by water to adjust consistency and the coriendar leaves. Adjust spices if needed. Cover and allow it to boil. Add tamarind water and boil again till you get the right consistency. Sambhar should be a bit thin if you want the idlis to absorb it. But if you want to eat idli like we dip dhokla in chutney, keep the sambhar a little thick.