Cut the thick hard stems of the mustard greens. Wash all the greens thoroughly and chop them.
Add all the greens to the pressure cooker along with turnips, green chilies, and salt. Add 1/3 cup water. Close the lid with the vent in the sealing position. Pressure cook on high for 4 minutes, then quick release the pressure manually. followed by natural release.
Using an immersion blender, blend/pulse them to a coarse texture. You don't want to make them completely smooth and pureed.
Heat a large pan on medium-high heat. Add ghee and let it melt. Add the dried red chilies and asafoetida. Add the onions and saute them for 6-8 minutes until they turn golden.
Add the ginger-garlic and cook for another minute. Add the tomato and spices
Add the saag to the tadka and give it a stir. Simmer for 5-6 minutes while stirring frequently, so the saag does not stick to the bottom of the pan.
Add maize flour (makki ka aata) to the saag. This will help to thicken the saag. Mix well and cook for another 5 minutes. Add hot water if needed to adjust consistency.
Once the saag has thickened to your liking, turn off the flame. Sarson ka Saag is ready to be enjoyed. Serve it hot topped with ghee or white butter along with makki ki roti.