The first thing you must do is soak the lobhia in water over night or for 7-8hours. This will make the beans soft and manageable.
Then, boil pre-soaked lobhia for 40 minutes or until very soft. Then, briefly boil tomatoes, peel off skin, and chop into large chunks.
Heat oil in a kadai and add cumin and cinnamon. Soon after, add garlic and onions. Once the onions turn golden brown add khumbi and fry for 5 minutes.
Add the tomatoes, coriander powder, cumin powder, turmeric powder, and cayenne. Cover and cook for 15 minutes, till the oil separates.
Add the cooked lohbia to the above stir it to mix well and leave it covered for another 15 minutes.
I'm so glad you mentioned where the recipe came from, because I used to cook this from that book many years ago, and know how really good it is. Now I have found the recipe again, it will again become a regular for me. Thank you.