Usually had by topping it with a generous dollop of ghee, Tadka Dal is one of the few dishes that is indulgent and healthy at the same time - the lentils are packed with proteins and the tempering of various condiments in hot oil or ghee does a good job of unlocking not only a mind blowing aroma but also the nutrition of the spice(South India's Spice Hero: How to Make the Famous Gunpowder)
The Regional Variations
Different regions within different states have their own unique recipe of Tadka Dal. Yes, it is that divergent! While some recipes play around with different types of lentils, most use different combinations of spices to tune up the flavour.(Blog: My Love-Hate Affair with Kerala's Cuisine)
The renowned Jiggs Kalra of Made in Punjab says, "The most popular and commonly found combination of lentils in Tadka Dal is that of Moong-Masoor and there are various types of tadka used - one is of jeera and the other is grilled onions, where the onions are lightly browned. There are also some dhabas where you will find a tadka of fresh garlic, onions and tomatoes."
What is called tempering in English, has over a dozen manifestations in India - tadka for Punjabis, vagharne for Gujaratis, the Hyderabadis call it baghar, while the Maharashtrians refer to it as phodni. Mustard seeds and curry leaves are a regular feature in south Indian cooking and also hold significance in Tadka Dal recipes. Cumin seeds are used for tempering the dish in northern states of Punjab and Haryana. While chana dal is used in Kolkata, toor dal is usually used in the south and masoor in the north.
So what makes Tadka Dal stand out from other lentil preparations in the country? Well, it isn't the list of ingredients but its unique preparation that takes the taste buds on an ambrosial journey. Unlike other dals, the tempering ingredients are not mixed with the lentils during the cooking process, but poured on top of it just before serving. However, there is a quintessential recipe that runs common all over the country. (Word of caution: never call it the authentic recipe or diehard fans with a different version might actually take offence).