Saute onion, carrots, and celery in a splash of water over medium-high heat in a large pot for about 5-8 minutes, until onions start to look transparent. Add garlic, potatoes, spices and salt and cook another minute.

Add all other ingredients (canned tomatoes, lentils, and vegetable broth). Bring to a boil, then reduce heat to low and let gently simmer about 20 minutes, until lentils are soft. Add spinach, if desired, and stir in until wilted. Add frozen peas, if using, to help it cool off. Season with additional salt and pepper, if desired.

Set the Instant Pot to the saute function and saute onion, carrots, and celery for a few minutes until onions appear translucent. Add a bit of water if needed. Add the garlic and spices and saute another minute.

Add the canned tomatoes, lentils, and vegetable broth and stir well. Cancel the saute function and set to high pressure for 15 minutes. Let it naturally release another 10 minutes at least before releasing pressure.

Open the lid and stir. Add spinach and peas if desired.