Soak tamarind in half cup of water and extract it's thick juice, discarding the residue.
Pressure cook toor dal for 3 whistles. Let it not be mushy.
Soak peas in enough water for about 4 hours.
Method
Wash carrot and beans under running water and cut them in to 1" long pieces.Transfer chopped veggies and peas in to cooking pan and let it cook till soft.
Add tamarind juice and jaggery,let the vegetables absorb the sweet and sour taste. Also add cooked toor dal and bisi bele bath powder. Mix well.
Wash thick poha in enough water and let it soak in water for about 10 minutes. Then squeeze and drain water from aval and keep it ready.
Include this poha or aval in to the gravy prepared in step 2. Add salt and some water too. Cook it again for some more time (5 mins). Then switch off.
Aval bisi bele bath is ready. Serve it along with boondi or potato chips or raita.
Note
Let aval bisi bele bath be of running consistency when you prepare initially. Because poha/aval tends to thicken with time.
The soaking time for thick poha varies based on the quality of poha.
Do not over cook toor dal, let it not be mushy.
You can add ghee seasoning with cashews. I have not added it.
You can replace peas by fresh ones in which case you need not have to soak them.