Bring a pot of salted water to a boil and cook your pasta according to package directions.
Warm 1/4 cup of water or veggie broth in a large saucepan on medium-high heat. Sauté the onion for 3-4 minutes until slightly translucent and fragrant.
Add the garlic, mushrooms, nutritional yeast, red wine vinegar and can of coconut milk and stir to combine. Cover and bring to a boil, then reduce heat to medium and allow the mushrooms to cook down, about 10 minutes, stirring occasionally.
Once the pasta has cooked, strain and reserve 1/4 cup of the pasta water.
Add the cooked pasta, 1/4 cup of pasta water, sour cream and salt and pepper to the mushroom sauce. Stir until well combined, turn off the heat and allow to sit uncovered for 5 minutes to thicken, stirring once or twice.
Serve and garnish with fresh parsley and lots of black pepper.