Cook the fettuccine to al dente according to package directions. Drain and set aside. 8 ounces fettuccine noodles

In a large skillet, heat the olive oil over medium heat. Add the sliced mushrooms to the skillet and cook for a few minutes until tender. Remove the mushrooms from the skillet and set aside. 1 tablespoon olive oil, 8 ounces baby bella mushrooms

Add butter to the skillet and cook over medium-low heat until melted. Whisk in the flour. Cook and stir for about 1 minute. 1¼ cup salted butter, 2 tablespoons all-purpose flour

Add the chicken broth and whisk well, then add the heavy cream, parmesan cheese, and garlic powder; stir well again. 1/2 cup chicken broth, 1 cup heavy cream, 3/4 cup freshly grated parmesan cheese, 1/2 teaspoon garlic powder

Increase the heat to medium and bring the sauce to a simmer for 1 minute, stirring constantly. Reduce the heat to low and season with salt and pepper to taste. salt and black pepper

Stir in the spinach. Cook over low heat for 1 minute then add the mushrooms and fettuccine. Stir well until all of the pasta is coated with the creamy sauce. 1 cup fresh spinach

Garnish with fresh parsley or basili and serve immediately.