To make saag first, clean, wash and chop all the greens (mustard, spinach and other). Once chopped soak them in water for 15 – 20 minutes to get rid of dirt particles.
Drain greens in a colander and set aside until required.
Heat ghee in a cooking vessel over medium heat and saute chopped onion, ginger, garlic and green chilies over medium heat for 10 minutes or until onion turn light brown in color.
Now add chopped tomato along with salt and red chili. Saute for 5 minutes over medium heat.
Once tomato is sauteed add chopped greens and stir nicely.Saute till greens turn soft in texture.
Add 4 Cups of water and let saag simmer over low heat till water is reduced to half and greens are completely cooked. Grind the saag in blender either to smooth puree or to coarse consistency, whichever way you prefer.
If you are adding corn kernels then saute them in a pan with 1 tbsp of oil and add to the pureed saag. If not, then simply skip this step.
Transfer saag into a saucepan and turn on the heat. Let it simmer over low heat while you prepare tempering.
For tempering, heat ghee in a small pan add cumin and once it starts crackling add dry red chilies. Pour tempering over the saag and mix nicely.
Cook saag for 10 minutes more and then turn off the heat.
Serve hot with Makki Ki Roti with more ghee on top.