Cook the noodles according to package directions until al dente. Drain, reserving 1/2 cup of pasta water.

Heat the butter in a medium pot over medium-high heat, add onion and sauté until golden, about 5 minutes.

Add the garlic and mushrooms, cook another 5 minutes, or until mushrooms begin to sweat down.

Add the flour, stirring to fully incorporate. Cook for 1 minute.

Stir in the wine and broth, bring to a gentle boil, reduce heat to medium, and cook another 5 minutes or until the sauce has slightly thickened.

Stir in the sour cream and parsley. Season with salt and pepper to taste.

Add the pasta to the mushroom sauce, toss to combine. Add in a little pasta water as needed to loosen the sauce.