Heat oil in Instant pot on saute mode. When hot, add onion, garlic and a pinch of salt. Cook for 2 mins, stirring occasionally. (See Recipe notes for Saucepan instructions )
Add veggies and mix in. Add red lentils, tomato purée, tomato, salt, seasoning, onion powder, garlic powder and mix in. Add a tbsp of tomato paste for additional tomato flavor (optional). Add lasagna sheets and water and mix in. (make sure to use small pieces and mix them in well else they tend to stick)
Close the lid and Pressure cook on manual hi for 3 mins **. Let the pressure release for 10 minutes, then if there is still pressure in the pot, manually release carefully and open.
Mix in the black pepper, pepper flakes and nutritional yeast. Taste and adjust salt and flavor(italian herbs, onion/garlic powder). Add some more salt, broth, tang(lemon) if needed to balance.
Fold in the spinach if using. Let sit for a minute. Then serve with pesto/basil and/or vegan ricotta/mozzarella, and garlic bread. You definitely need some vegan cheese for a more lasagna like flavor. Fold in some into the soup while still hot and use more for garnish.