Wash the dal and take in pressure cooker.
Add water, turmeric powder, hing and pressure cook them for one whistle in medium and five minutes in low flame.
Once pressure releases open and mash the dal.
Wash and cut the knol khol as cubes
Take small lemon sized tamarind and extract it adding little hot water.
Heat oil and temper with mustard and urad dal.
Once it browns add the chopped onions and saute till transparent.
Then add the chopped tomatoes and saute till mushy.
Then add the cubed kohlrabi
Saute for 5 minutes and switch off the flame.
Add red chilli powder, coriander powder, sambar powder to cooked dal.
Now add the vegetable mixture to it.
Mix everything and add tamarind extract to it.
Pressure cook for 2-3 whistles. Once pressure releases open and garnish with coriander leaves.
Serve Knol khol sambar with hot rice.