Take 1 cup of black dal in a bowl and wash it twice or thrice in clear water. Then soak it in water for 6 to 7 hours before cooking and keep it aside. Soaking make dal more smooth and easy to digest. Drain the water when you are ready to cook.
Take a pressure cooker on a stovetop on medium heat and add 1 tbsp oil in it with 1 tsp cumin seeds and 1 bay leaf. Saute them.
When cumin seeds start to sizzle add chopped onion and saute them until they have golden texture.
Then add chopped tomatoes & ginger paste or chopped green chili and saute them for 2 minutes.
Add soaked urad dal in with 3/4 tsp turmeric powder, 1/4 tsp red chili powder, 1/4 tsp asfoetida, and salt to taste with 3 cups of water.
Mix all the ingredients well and close the cooker lid. Pressure cook for 4 whistles on medium heat. Then before the 5th whistle comes sim the gas stove for 5 to 7 minutes and after that turn off the heat.
When the pressure releases down naturally you see the lentils have cooked.
Turn on the gas and simmer if for 5 minutes. Then with the help of a spoon or masher mix them properly so that your dal looks thick in texture. Add more water if need to adjust.
Lastly, add 1/4 tsp garam masala powder and 1 tbsp chopped coriander leaves.
Mix them well and turn off the gas and the urad dal is ready to serve.