Soak the vaal beans in water for 6-7 hours, after 6-7 hours drain the water and pressure cooker them along with water and salt for 2 whistles, sieve the vaal beans and keep the boiled water aside, we’ll use in further cooking.
Now heat oil in a non stick kadai, when oil gets hot add in ajwain, when ajwain starts crackling turn the heat off and add gram flour, turmeric powder, spicy red chilli powder, kashmiri red chilli powder and mix all the spices well.
Now turn the gas on and add vaal beans and again mix well then quickly add water in which vaal beans were boiled, now check the gravy and add salt according to taste.
Now add jaggery and mix well, now cover and cook it for 6-7 minutes, after 6-7 minutes add lemon juice again cover and cook for 2 minutes.
After 2 minutes turn the heat off and take out the butter beans curry in a serving plate, garnish it with some coriander leaves and serve with roti, puri or rice.