Turn on Instant Pot. In the inner pot of IP, add chopped mustard greens - stems, mustard greens - leaves, chopped spinach, onion, ginger, garlic, green chili, coriander powder, turmeric powder, salt to taste, and water. Close the Instant Pot.
Turn on Instant Pot to manual / pressure cook mode (high) for "0" minutes, vent sealed.Note: "zero" minutes is not a typo.
When Instant Pot beeps, quickly release pressure. Open the IP lid.
(Optional) Using a hand blender or immersion blender, pulse the greens few times, until desired consistency. You can puree the greens as well.
Turn on saute mode (high), add maize flour, mix well. Cook for 2-3 minutes.
Prepare the tempering on a stove top. On a medium-high heat, in a sauce pan, add oil+ghee. When oil is hot, add cumin seeds, asafoetida, garlic, onion. Saute until light brown in color, around 2-3 minutes. Turn off heat. Add red chili powder, pour this tempering over greens.
Add garam masala, some lemon juice. Mix well. Turn off Instant Pot.
Sarson da saag or mustard greens is ready to be served. Enjoy!!