In a small bowl, combine Spice Mixture ingredients.
Place fish in one even layer in a steamer basket and sprinkle with spice mixture. Set aside.
Add olive oil to the Instant Pot. Using the display panel select the SAUTE function.
When oil gets hot, add onion to the pot and saute until soft, 3-4 minutes. Add garlic, ginger and cumin and cook for 1-2 minutes more.
Add broth to the pot and deglaze by using a wooden spoon to scrape the brown bits from the bottom of the pot.
Add lentils to the pot and stir to combine.
Insert a steam rack or riser, and carefully lower the steamer basket onto the riser.
Turn the pot off by selecting CANCEL, then secure the lid, making sure the vent is closed.
Using the display panel select the MANUAL or PRESSURE COOK function*. Use the +/- keys and program the Instant Pot for 5 minutes.
When the time is up, quick-release the pressure. Check the fish for doneness. If it is not quite cooked through close the lid and leave on KEEP WARM for another 3-5 minutes.
Carefully remove the steamer basket and riser from the pot. Add lemon juice, 3/4 tsp salt and 1/4 tsp pepper to the lentils and stir.
Serve the fish on a bed of lentils.
Notes
*The MANUAL and PRESSURE COOK buttons are interchangeable.