Begin by boiling your fettuccine in salted water until it’s al dente. Drain and set aside, but save a splash of that pasta water to help with the sauce later if needed.
Heat 2 tablespoons of olive oil in a large skillet over medium heat. Add the sliced mushrooms and minced garlic. Sauté them until golden brown, ensuring the excess liquid has evaporated. Season with salt and black pepper for added depth.
Melt 1/2 cup of unsalted butter in a medium saucepan over low heat. Stir in 1 cup of heavy cream and 1 cup of grated Parmesan cheese. Add 1 teaspoon of garlic powder, then season to taste with salt and white pepper. Stir constantly until the sauce is smooth and creamy.
Transfer the cooked pasta to the skillet with the mushrooms. Pour the Alfredo sauce over the top. Toss gently to coat all the pasta and mushrooms evenly in the rich, velvety sauce. Add a splash of reserved pasta water if the sauce is too thick.
Transfer the pasta to serving bowls or plates. Sprinkle with freshly chopped parsley for a bright, herbaceous finish. Serve immediately and enjoy every creamy bite!