Set your InstantPot to sauté mode.
When hot, add 2 tbsp oil, mustard seeds, cumin, turmeric, asafetida, and curry leaves.
Sauté until the mustard seeds start to pop.
Add the spinach, dal, water, and salt, and stir to combine.
Close the lid and set to sealing.
Pressure cook for 5 minutes on high/normal pressure and allow the pressure to come down on its own when done (usually takes about 20 minutes).
Open and stir to combine before adding a the lemon juice.
Serve over rice or with chapathi!