Place the fettuccine noodles in the instant pot. You may break the noodles in half so you can fit them easily in the pot.
Add the salt and water, make sure the pasta is covered in water.
Now add the vegetables - frozen peas, baby carrots and baby spinach leaves on top.
Close the instant pot with lid in sealing position and cook in high pressure for 3 minutes.
Once the cooking is done, wait for a natural pressure release for about 12 minutes, after which you can carefully and gradually do a manual pressure release to release any remaining pressure.
Once the pressure is all released, carefully open the lid and add the heavy cream and cheese also to the instant pot. Gently stir everything to combine with the noodles! The delicious and creamy alfredo pasta is ready to serve!