In a large bowl, combine ricotta, spinach, 70g of the parmesan, garlic, egg, salt, and pepper. Mix well.
Spread 100g tomato sauce on bottom of a cake pan (that fits in your inner pot).
Lay the cooked lasagne sheets onto a chopping board and spread ricotta filling on top of each sheet, keeping filling inside edges of the past sheet. Roll each lasagne sheet up lengthwise and arrange inside cake pan.
Spread remaining sauce over lasagne rolls and top with remaining Parmesan cheese. Tightly cover cake pan with foil.
Pour water into Instant Pot and add trivet, create a foil sling to carefully lower the cake pan into the inner pot.
Secure the lid and select Pressure Cook and adjust the time to 12 minutes.
When the cooking program finishes, perform a quick pressure release and unlock the lid.
Remove pan using foil sling and then remove foil from pan and serve.