Cooking: Heat oil in a pan. Once the oil is hot, add cumin seeds. ( To check temperature, drop a grain of cumin into the oil and see if it crackles. If it does, the oil is hot enough). Add the onions and stir for 2-3 minutes till onions are transluscent in colour. Add the tomato puree and chopped tomatoes. Cook for 2-3 minutes till the tomatoes are cooked.