Bring a large pot of salted water to a boil and cook the pasta al dente according to package instructions. Drain and set aside.
In a large skillet, melt butter over medium heat. Add sliced mushrooms and minced garlic, sautéing until mushrooms are golden and garlic is fragrant.
Pour in the white wine to deglaze the pan, scraping up any browned bits. Allow to simmer until the wine is nearly evaporated.
Sprinkle in flour and stir; cook for 1-2 minutes to remove raw flour taste.
Add the heavy cream, lemon juice, onion powder, oregano, salt, and pepper, and simmer until the sauce thickens slightly.
Add the cooked pasta to the skillet, tossing to coat with the sauce. Stir in grated Parmesan cheese until melted and evenly distributed.
Serve the pasta hot, garnished with chopped fresh parsley.