Start by measuring the moong chhilka dal and the rice. I usually use a 3:1 proportion but you can try other proportions as per your liking. Add the measured dal and rice to a big bowl and rinse with cold water and drain 3-4 times.
After the final rinse, add 4 times water to the dal and rice mix. So if you used a total of 1 cup of dal and rice (measured together), add 4 cups water and let the mix soak while you prep other stuff.
Gather the other ingredients while the dal and rice soak. Peel the onion and chop roughly. Wash the tomato and chop in chunks. Also chop the garlic and peeled ginger. You can chop or slit a green chilli if using.
Place the pressure cooker on medium high heat. Add ghee and wait for it to melt. Once hot, add cumin seeds and heeng (asafoetida).
Wait for the cumin to pop. Once you hear the seeds pop and sizzle, add chopped onions and ginger. Stir to coat with the ghee and let these cook on medium heat till translucent.
Once the onions are done, add chopped tomatoes, garlic and green chilly. Soon after, add salt and turmeric.
Cook till the tomatoes are mushy. While they cook, drain and reserve the water of the rice and dal into another bowl. The idea is to toast the soaked dal and rice with the tadka. Alternatively, you could also use your clean hands to grab the soaked rice and dal and add them gradually. Toast the rice and dal with the tadka for 3-4 minutes. This step is optional. You could also add the water and dal rice mix altogether.
Now add the reserved water to the contents of the cooker. Add an optional sprinkle of garam masala and close the pressure cooked lid.
Pressure cook on high heat for 1-2 whistles. After that remove the pressure cooker from heat and let the pressure release naturally.
Once the pressure is released, open the pressure cooker and mix to combine the contents. Ladle the Khichdi in deep plates or bowls.A few cracks of black pepper and a dollop of ghee later, comforting Khichdi is ready to serve!