Cook the pasta according to the instructions on the box.
While the pasta is cooking, heat olive oil in a large pan over medium heat. Add the sliced mushrooms and cook for 8-9 minutes until they are golden brown and tender. Season with salt to taste. Remove the cooked mushrooms from the pan and set aside.
In the same pan, add the butter and minced garlic. Cook until the garlic becomes golden and fragrant.
Stir in the miso paste and reserved pasta water, making sure to scrape up any browned bits from the bottom of the pan. Let it simmer for a minute.
Pour in the heavy cream and let it cook for another minute, allowing the flavors to meld together.
Add the cooked mushrooms back to the pan, give everything a good stir.
Add the cooked pasta to the sauce and toss until well coated.
Sprinkle in the grated Parmesan cheese and continue cooking until the cheese has melted and the sauce has thickened slightly.
Serve hot and enjoy your creamy mushroom pasta!