Clean, wash and soak toor dal in water for 15 – 20 minutes. Make sure to wash the pigeon peas nicely with water 2 - 3 times before soaking.
Transfer soaked dal to a pressure cooker, along with green chili, salt, turmeric powder, ginger garlic paste, and chopped tomato. Add 4 cups of water. Stir to combine. Seal the pressure cooker with the lid. Cook dal for two whistles over low heat. Allow the steam to release naturally.
Open the lid of the pressure cooker. Taste the dal and, if required, add more salt and seasoning to the dal. If the dal is too thick, add more water to get the desired consistency. Turn on the heat and allow arhar dal to simmer while you prepare the tadka.
Prepare tadka, heat ghee in a small pan. Add cumin, asafoetida, red chilies, chopped garlic, and onion. Fry till onion and garlic is light brown. Continuously stir the tadka while frying. At last, add red chili powder and turn off the heat.
Pour hot tadka over the arhar dal. Stir to combine. Sprinkle chopped fresh coriander. Stir to combine. Seal the pressure cooker with a lid for 5 minutes. This way flavor and aroma of tadka are nicely combined with the dal.
Garnish with fresh chopped coriander leaves.
Serve Arhar Ki Dal warm with rice.