Turn pressure cooker to saute on medium heat and add butter.
Once butter is melted add onion, carrots, celery, and mushrooms.
Saute the vegetables until they are softened, about 5 mintues.
Stir in the oregano, thyme, garlic, salt, and pepper.
Put the noodles in the pot on top of the cooked vegetables.
Pour the chicken stock and water over the noodles. Make sure the noodles are completely covered with liquid. Add more water if necessary.
Set the pressure cooker to manual high pressure. Cook for 9 minutes.
Perform quick pressure release. Remove the lid and stir in the heavy cream.