1. Wash 500 gms chaulai thoroughly and chop them.
2. In a kadai, heat 2 tbsp oil. add 1.5 tsp black gram skinned / sabut urad dal dhuli, 1 tbsp coriander seeds, 1/4 tsp methi seeds / fenugreek seeds, 1/4 tsp black peppercorns, 1.5 tsp cumin seeds, 2 dried red chillies (broken). stir on low flame until urad dal turns golden.
3. Then add 1 tbsp lemon sized piece of tamarind, 7 small shallots. stir for a minute.
4. Add 1 big chopped tomato and 1 chopped green chilli. cook till tomatoes become soft and mushy.
5. Next add 3 cloves of garlic. stir till garlic gets cooked.
6. Once masalas are cooked, add 1 tsp jaggery, the chopped chaulai. stir for about 3 minutes.
7. Once mixed well, add 1.5 cups water. bring the entire mixture to a boil. once it boils, turn off the flame.
8. Add salt to taste and let it cool completely. transfer to blender jar and make a puree. set it aside.
9. Heat 2 tbsp oil in a pan, add 2 tsp mustard seeds, 1 broken red chilli. switch off the flame and add 1/4 tsp turmeric powder, a pinch of hing / asafoetida, few curry leaves and then the chaulai puree.
10. Now switch on the flame and let this mixture come to a boil.