In the summer, you would find this rasam very tasty .. here is how you make it.. Take a very sour mango ( be sure !), wash it thoroughly and cook in a pressure cooker along with moong dall... after it is cooked remove the pulp and add to the moong dall, add cilantro, curry leaves, rasam powder and salt to taste, bring to a boil and then add the "tadka" shown in the clip.. Tip: to find out if a mango is sour inside, examine the skin .. it should be deep green and have very little yellow dots on its surface.. it should be white inside when cut and should not be fibrous..