Turn on the Instant pot saute mode and heat 1 tablespoon of sesame oil or ghee preferably.
Add ½ teaspoon cumin seeds, ½ teaspoon mustard seeds, a pinch of fenugreek seeds( around 8 to 10 seeds), chopped ginger & garlic pieces, hing, ground turmeric, red chilli pieces, slit green chilli and curry leaves. Saute them for a few seconds until you get a nice aroma.
Now add ½ cup of chopped onion and a little salt with it to help onions cook faster. Saute the onions for a couple of minutes until they turn translucent.
Then add chopped tomatoes and a little salt with them. Cook for a minute or two.
Next, add the washed dal and 1.5 cups of water with it and mix well to make sure nothing is sticking to the bottom of the pot.
Note: If you want, you can use a trivet to place your rice bowl on top of the dal (pot in pot method). The cooking time given below will be good for both rice and dal.
Cancel saute mode, close the Instant pot lid with the vent in sealing position, turn on manual mode on high pressure for 10 minutes.
Once the Instant pot beeps and turns off, do a natural pressure release for 10 mins and then turn the knob to VENT position to release the rest of the pressure until the pin drops.
Open the lid and turn on saute mode. Use a whisk to mash the dal if you prefer. Add the chopped spinach and salt and give it a mix. Cook it for 2 or 3 minutes until the spinach is cooked and dal reaches desired consistency. Add more water if you prefer.
Now turn it off, add lemon juice after a couple of minutes and garnish with cilantro to serve hot with rice or roti or as a soup.