Wash and soak the dals for 1 hour. Then drain the soaking water and add fresh water up to 1 inch above the dals and cook them in the pressure cooker for 6 whistles until the dals are soft and mushy.
Wash, peel, deseed and chop the lauki or bottle gourd and keep aside.
Similarly chop the onion and tomato and keep aside.
Remove tamarind extract with a lemon size ball of tamarind and 1 cup hot water and keep aside. I have detailed the process of removing tamarind extract in many recipes before, so I'm not writing it here again . You can check this post for the same. Now in a deep pot add 1 tbsp ghee or oil (I prefer ghee but feel free to use oil). Once it becomes hot add in the crushed garlic cloves and saute for 2 mins until the garlic becomes golden and fragrant.
Now add in jeera, hing, kadi patta and 2 broken red chillies and saute for 5 seconds. Take care not to burn the jeera.
Now add in the onions and saute till they become translucent.
Add 1 tsp ginger garlic paste and saute till raw smell goes away.
Now add in the tomatoes and add salt to taste. The salt will cause the tomatoes to release their juices and cook down sooner. Cover and cook for 2-3 mins until the onions and tomatoes are soft and mushy.
After 2 mins add in the masalas, kashmiri chilli powder, turmeric powder and coriander powder and saute. If the masala is becoming too dry, add 2 tbsps of water to incorporate moisture.
Cover and cook for 2-3 mins until the oil separates and comes up.
At this stage add in the tamarind extract and 1 cup water and bring it all to a boil.
Once the water starts boiling, lower the flame and add in the chopped lauki. Cover and cook for 10 mins until the lauki is 95% done.
After 10 mins, add in the mashed dal and mix well. Add another cup of water to thin it down a bit and and cook the dal with the masalas for another 2-3 mins on high flame. Adjust the consistency further if required.
Check for salt again and adjust if required.
Finally garnish with chopped coriander. Its done!
Your lauki dal is ready. Enjoy with steaming hot rice or rotis.