Pour cream and water into the pot, add in noodles, pressing them down so they are covered with the cream and water. Add in garlic, mushrooms, and seasonings. Place cut butter slices and cream cheese slices around the pot, stir to mix, making sure noodles are submerged.
Close and lock in lid, setting the steam release knob to sealing position. Select cook, for 7 minutes. Once done, let the pot sit for 25-30 minutes, allowing the natural release. Carefully open, and stir the pasta. Add in the shredded parmesan cheese and stir until it has melted into the sauce. If the Alfredo sauce is too thick, add in additional heavy cream, a Tablespoon at a time until it reaches your desired consistency.
Additional: Garnish with chopped parsley or grated/shredded parmesan cheese, if desired.
This recipe is for 4 servings. I have doubled the batch, and it still works perfectly. I have also been out of heavy cream and prepared it with milk, and it is still good, just not as thick, but still creamy. More or less mushrooms can be added, as well as chicken, shrimp, etc. We don’t like a lot of other “things” to overtake the taste of the pasta, so this is a perfect balance. I let it sit for an additional 25-30 minutes, but you can shorten that time if necessary. Just be sure to allow it to sit for 5-10 minutes and then release the remaining steam in short bursts or sauce may spit out.